TEXT: Codex of the 
  Infinite Planes
  The Essential Guide to the Planes of Existence
  Volume XXIII:
  Clockwork Nirvana of 
  Mechanus
  
  The Essential Guide to the Planes of Existence
  Volume XXIII:
  Clockwork Nirvana of 
  Mechanus
  Written & Designed by  “Weird Dave” Coulson
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  Codex of the 
  Infinite Planes
  
  Volume XXIII  |  Clockwork Nirvana of Mechanus
  3
  Volume XXIII: Clockwork 
  Nirvana of Mechanus
  “The song of harmony rings sweet and true on the plane 
  of Mechanus like nowhere else in the multiverse. Truly 
  it earns the name nirvana – a peaceful serenity settles 
  over the clockwork gears and moving pieces of the 
  landscape. Everything moves with purpose, determination, 
  and singular focus, and nothing is left to chance. If 
  there’s a blueprint for peace, I can see no better guide 
  than Mechanus, though even such a perfectly working 
  mechanism has its own problems from time to time. The 
  constant tune-up and maintenance, though, is part of the 
  intricate cycle that is, in a word, breathtaking.”
  Issilda the Unbreakable
  Absolute order brings absolute harmony, at least in the 
  Clockwork Nirvana of Mechanus, the most orderly plane 
  in all the multiverse. There is no subtlety or guile present 
  in this plane of stark truth and fact, but neither is there 
  passion or emotion. Everything moves and happens with 
  deliberate and driven purpose according to a plan, though 
  most, including many of the residents and gods, are blind 
  to that plan – a situation that suits the inhabitants just fine.
  Mechanus is a plane filled with enormous gears, like the 
  internal working of a clock, each gear moving in perfect 
  concert with adjacent gears. Some gears are as small as 
  10 feet across, while most are larger, spanning hundreds 
  or thousands of miles across. They all move, though many 
  are so expansive that their movements are imperceptible 
  to those moving and living on them.
  In this plane of constant motion, of gear teeth moving 
  with absolute precision, everything is in perfect balance. 
  Day and night, light and dark, they are all parceled out 
  in equal portions without change or deviation. The sheer 
  scale of the operation on Mechanus is mind-boggling and 
  has thus far eluded attempts at deciphering, though some 
  have dedicated their lives to understanding its meaning. 
  The Confederacy of the Cog are a group of brilliant 
  artificers who are wholly devoted to understanding not just 
  how Mechanus works, but why.
  Life exists in the Clockwork Nirvana as well, though 
  most of it is mechanical or constructed in nature. The 
  most numerous and recognizable of Mechanus’ resident 
  races are the modrons – legions of geometrically shaped 
  creatures living, breathing, and operating to keep 
  Mechanus ticking and running smoothly. From the sphere-
  like monodrones, to the cube-like duodrones, all the way 
  up to their supreme god, Primus, they are all devoted to 
  keeping the gears running. They don’t know why, they don’t 
  care why, and usually they only have the barest hint at what 
  exactly their duties accomplish. But they accomplish them 
  with focused intensity and child-like glee.
  The clockwork precision of Mechanus is not just found 
  in the continually running gears and moving pieces. 
  There’s a sense of rigid order that pervades every facet, 
  and affects everyone equally that travel its realm of endless 
  gear. The regular variance of chance is dampened to an 
  extreme degree, so that the predictable outcome is the 
  most likely, even in an otherwise unpredictable situation. 
  Warriors swing their weapons with the same amount of 
  force, regardless of how much they want to inflict more or 
  less. Magic and spells are affected in similar fashions.
  There are many comparisons between Mechanus and 
  Arcadia, and the insect-like formians are found on both in 
  great numbers. However, whereas Arcadia relies upon a 
  complex set of legal laws and regulations maintained by 
  the Lex, Mechanus’ laws are ingrained in the very fabric 
  of the plane. For many of these laws, breaking them is 
  simply not possible, or at least not to the general populace. 
  Certain magical artifacts and beings are said to affect the 
  laws of Mechanus, but these individually powerful aspects 
  rarely visit the Clockwork Nirvana.
  There are other, stranger manifestations in this plane 
  of absolute order. The Word of Law is an enigmatic figure 
  that twists the natural power of Mechanus into immensely 
  powerful written words, like scrolls. Few has seen this 
  strange being face to face, and most believe it is an entity 
  from another plane pushing into the Clockwork Nirvana. 
  The Glass God is another one of these powers though its 
  origin is more overt – it comes from the Far Realm and 
  seems to be enforcing a kind of unknown, alien order into 
  the rigid structure of Mechanus, spreading and infecting 
  out like a disease.
  It surprises some to learn that there are portions of 
  Mechanus devoted to junk and refuse, along with the raw 
  materials that make up the gears. These are, of course, all 
  perfectly orderly and organized, and the modrons that tend 
  to them and many other realms in the Clockwork Nirvana 
  take their jobs very seriously. They have strict rules 
  preventing outsiders from taking scrap or raw materials 
  outside of the designated zones.
  The great machine of Mechanus is constantly moving, 
  in perfect synchronization with countless delicate gears 
  across hundreds of thousands of miles. Or at least, that’s 
  the image. The reality is that there are any number of parts 
  that break down across the gear landscape, and a great 
  many outsiders work to harvest the valuable metal for their 
  own purposes. Mechanus exists as the pinnacle of order in 
  the multiverse, but it is not perfect, and there are plenty of 
  cracks in its façade for many to exploit.
  Lay of the Land
  Mechanus consists of a single layer, infinite in size 
  across all directions, with no natural ground to be found. 
  Everything is manufactured, though in such a strange 
  mechanical plane, the metal is natural, so perhaps it 
  would be more accurate to state that there is no natural 
  vegetation. One particularly strange aspect of Mechanus 
  is the gravity – it’s subjective based on the gear you’re 
  traveling on. Many gears and cogs are perpendicular to one 
  another, but a traveler can move from one to the other by 
  simply stepping onto it. They are re-oriented to the new flat 
  surface as “down” while everything else remains in place.
  The effect is strange but the natives are used to it, and 
  the constructs that move around the plane are completely 
  unphased by the shift in gravity and perspective. This does 
  mean that the concept of direction is difficult to convey, 
  but there are tools built by modrons and other natives that 
  help anchor and reference using magnetic obelisks around 
  
  Volume XXIII  |  Clockwork Nirvana of Mechanus
  4
  Mechanus (see the Traveling Around section for more 
  details).
  Though Mechanus has a single vast layer, it is divided 
  into geographic realms, identified by planar scholars and 
  adopted by natives for a common vernacular. The Great 
  Gears and Scrap Tracts are all part of the vast machine of 
  Mechanus and can help travelers navigate around.
  Great Gears
  The vast majority of Mechanus is comprised of a broad 
  region referred to as the Great Gears. This is the core of 
  Mechanus, consisting of innumerable gears and cogs, all 
  moving in synchronization with one another. There is no 
  region of open sky in the Great Gears, as there are always 
  more cogs above and below any particular cog, usually 
  within sight. The closeness of the gears makes some 
  regions almost building-like in their structure, with moving 
  cogs functioning as walls.
  Most of the population of Mechanus are found in the 
  Great Gears, including the modrons and the factories 
  that produce the inevitables. Some of the larger cogs are 
  populated by transplanted populations from across the 
  multiverse, including devilish outposts and angelic watch 
  towers. The formians and their expansionist tendencies 
  create conflicts with the local populations wherever they 
  go, which is partly why they have moved into Arcadia.
  Scrap Tracts
  Sometimes, gears break down and need to be replaced. 
  The maintenance of the cogs across the plane is left to the 
  modrons. They dispose of broken gears and pieces into 
  the regions known as the Scrap Tracts. There are multiple 
  Scrap Tracts housing the refuse and junk produced by the 
  natural processes of Mechanus, and each one is contained 
  in a vast cylinder of gray steel.
  The cylinders are hundreds of miles across with multiple 
  entrances, and inside are the vast collections of scrap 
  metal from across the plane. Metallic golems patrol the 
  interior and exterior, but each Scrap Tract is so large as 
  to be impossible to patrol thoroughly. Scavengers of all 
  kind regularly raid the cylinders for parts to fuel their own 
  purposes, the most numerous and tenacious being the 
  Gearlost.
  Each Scrap Tract is assigned a unique serial number 
  for identification, from Alpha One to Omega Ninety-Nine. 
  Some of them house specific types of scrap, such as 
  Scrap Tract Gamma Eleven where all magical refuse is 
  contained. Finding a specific cylinder is difficult, however, 
  as the modrons are the only ones who know, and they are 
  forbidden from sharing this information with outsiders.
  Eventually, the refuse in each Scrap Tract is broken 
  down and turned into new gears and cogs, which are used 
  to replace worn gears and shore up destroyed sectors. 
  As with everything on Mechanus, there’s an ordered time 
  for this conversion, but the scale and relative isolation of 
  the Scrap Tracts makes understanding the exact timing 
  difficult for outsiders.
  Cycle of Time
  Time passes normally on Mechanus, perhaps more 
  normally than anywhere else in the multiverse. A day 
  in the Clockwork Nirvana is divided perfectly into three 
  segments, each consisting of eight hours, but there is no 
  sun or change in light to mark the passage of time. Instead, 
  placed around the plane are massive golden bells, known 
  as Nirvana Bells, that chime out in perfect synchronization 
  to mark the new segment (ringing once, twice, or thrice 
  depending on the segment). They are clear and loud, 
  and the residents usually have smaller devices timed to 
  the Nirvana Bells to help them stay in synch with the 
  movements of the plane.
  Surviving
  The geography of Mechanus is not inherently dangerous 
  to travelers. However, getting caught in the cogs can pose 
  a serious threat to life and limb; details of this are found 
  under Hazards & Phenomena.
  Getting There
  Portals and gates leading to Mechanus never randomly 
  appear or disappear. They may have extremely long cycles 
  of inactivity, but they always operate on a regular schedule 
  in cadence with the cog they lead to on the plane. A gate 
  leads to the center of a specific cog somewhere in the 
  Great Gears and its opening is tied to the movement of 
  the interlocking gears. Some may open for a minute every 
  hour, some open for an hour every day, while some open 
  for exactly 13 minutes once every decade.
  Without the greater context, the opening of these gates 
  can feel random, but anyone who knows Mechanus knows 
  that it is anything but haphazard. It simply requires a wider 
  understanding to fully grasp.
  Portals to the Clockwork Nirvana are normally marked 
  by a constructed archway of some sort, usually metal, often 
  containing a gear-like pattern on the surface. Opening 
  these portals usually requires completing a set of verbal 
  and somatic gestures within 5 feet of the opening while 
  possessing a small cog in hand. Aspects of the ordered 
  regulation of Mechanus often bleed through the multiverse, 
  and it’s not uncommon to have buildings of industry built 
  around these portals, regardless of actual knowledge of the 
  portal’s presence.
  There are certain gates that are activated by events that 
  occur on regular schedules. The most widely known of 
  these are the gates along the path of the Great Modron 
  March. During this time, the modrons of Regulus march 
  across the multiverse in a massive line, following a 
  predetermined path that flows through multiple planar 
  gates. As with everything on Mechanus, the Great Modron 
  March occurs on its own ordered schedule, but few have 
  the scope of knowledge to understand that schedule.
  
  Volume XXIII  |  Clockwork Nirvana of Mechanus
  5
  Traveling Around
  For a plane of moving gears and grinding cogs, movement 
  around Mechanus is surprisingly straightforward and easy. 
  Everything in Mechanus is connected to something else, 
  usually gears connected to adjacent gears via cog teeth, 
  so it’s possible to reach any destination in the Clockwork 
  Nirvana from any starting point. It may take some time, but 
  there is a path.
  Part of traveling around Mechanus is moving along 
  the faces of the gears. A person standing on a gear is 
  standing upright, but gravity is situational, so that same 
  person could step onto an adjacent perpendicular gear 
  and orient immediately to the new “up and down” without 
  any ill effect. This all makes moving physically relatively 
  straightforward, and it’s coupled with the fact that the 
  movement of the gears – all are in motion – are not felt by 
  a person or object on the gear. Nothing flies off, regardless 
  of how fast the gear is moving.
  Because of Mechanus’ three-dimensional landscape and 
  no set horizon, concepts such as north, south, east, and 
  west do not make sense on the plane. Instead, the entire 
  plane is divided up into an infinite coordinate system 
  developed by Primus, the god of the modrons and one of 
  the oldest beings in the multiverse. Using the magnetic 
  obelisks around Mechanus along with devices that 
  resemble sextants, a person can find out where they are 
  on the great grid of the plane, a location identified by three 
  numbers known as the exx, wyy, and zee. Primus, in the 
  center of Regulus, is at [0,0,0], and the numbers increase 
  out to infinity from there. They can be negative or positive 
  reflecting the relative direction from Primus. 
  Every site and gear in Mechanus has coordinates on the 
  exx-wyy-zee grid relative to its distance to Primus. Every 
  1000 feet is marked with 1, so the point [1,1,1] is 1000 
  feet from Primus in three directions, while [-1, -1, -1) is 
  1000 feet from Primus in three directions in the opposite 
  direction. To the modrons and other natives of Mechanus, 
  the coordinate system of exx-wyy-zee makes perfect sense, 
  and they have a hard time adjusting to the relatively flat 
  landscape of the rest of the multiverse.
  The Powerful and Mighty
  As the plane of rigid ordered structure and clockwork 
  precision, Mechanus draws and generates a variety of 
  interested powers. Some look to exploit the weaknesses 
  inherent in such a massive machine, slipping between the 
  cracks, while others try to harness the capabilities of the 
  gears and cogs that fill the landscape. Mechanus is also 
  home to one of the oldest beings in existence, Primus, who 
  is said to rival Asmodeus in age and sheer influence. 
  Confederacy of the Cog
  Artificers from across the multiverse are drawn to 
  Mechanus. It’s an entire plane of constructed material, on 
  a scale unfathomable anywhere else, with living creatures 
  of metal and stone existing naturally in such an unnatural 
  environment. As they came to study, the artificers shared 
  their knowledge, and from that original community 
  came the Confederacy of the Cog. The original founding 
  members built the Transcendent Academy to share their 
  discoveries and inventions, and to train new members.
  Overall, the members of the Confederacy have done 
  much to advance the artificer art in the multiverse. 
  Individuals and groups within the group have documented 
  many of Mechanus’ internal processes, though the sheer 
  scale of that project is going to likely require generations 
  of artificers working and expanding their documentation. 
  Cog Confederates (as they are also known) have expanded 
  the Transcendent Academy into a massive sprawling site, 
  with dozens of large laboratories and hundreds of personal 
  chambers to house their experiments and findings.
  The Confederacy of the Cog are led by a thirteen-
  member Cog Council, who are made up of members 
  voted upon by their peers once every five years. There 
  is no leader, so each individual on the Cog Council has 
  equal voice in all matters brought before their chambers, 
  though strong members tend to dominate such meetings. 
  Committees in the Cog Council meet regularly to approve 
  new members, settle disputes, and hear reports on the 
  advancement of artificer work within the academy and the 
  multiverse at large.
  The vast majority of the Cog Confederates are clockwork 
  engineer artificers, but they welcome all who wish to learn 
  the artificer art into their halls. Gnomish gem binders 
  from Bytopia, elven livewood sculptors from Arbora, 
  battlesmiths from the world of Eberron, goblin alchemists 
  from Ravnica, and the strange wonderkin from the Plane 
  of Dreams can all be found in the Transcendent Academy. 
  It is a place of invention and creation, but under strict 
  guidelines – chaotic artificers chafe under the mounting 
  list of rules and regulations that guide everyday life in the 
  academy and Mechanus as a whole. Few last long.
  Formian Hive-Cities
  The ant-like formians are one of the few non-construct 
  creatures native to Mechanus. They are as industrious and 
  focused as the insects they resemble, and on the cogs of 
  the Clockwork Nirvana they have built enormous hive-
  cities. Each cog consists of a single colony of formians, 
  and each colony is ruled by a single queen. The colonies 
  themselves are constructed of compacted metallic dirt 
  pulled together from creation vats operated by formian 
  drones – other drones bring scrap metal to the vats, which 
  are then broken down and used to build the colony. Most 
  colonies resemble smooth-sided towers stretching up 
  hundreds of feet.
  The vast majority of the hive-cities on Mechanus are 
  clustered around a large cog that houses their largest 
  colony – Arkitan, which in the clicking language of the 
  formians means “center.” It is the home of the Scion Queen 
  Mother, the greatest and most powerful of the formian 
  queens in all the multiverse, and it is by her will the 
  formians expand out, both through Mechanus and beyond. 
  Large colonies have been established in the Peaceable 
  Kingdoms of Arcadia, and there are rumors of hidden 
  hive-cities within select cubes floating through the Infernal 
  Battlefield of Acheron.
  
  Volume XXIII  |  Clockwork Nirvana of Mechanus
  6
  The Scion Queen Mother encourages the queens of the 
  hive-cities to push forward and expand, and this results 
  in a lot of conflict between the individual colonies. This 
  is perhaps the only reason the formians haven’t proved a 
  greater threat, for while they are utterly focused on the 
  health and safety of their individual colonies, they seem 
  to have little thought for their species on a whole. The 
  Scion Queen Mother in Arkitan is of a different mind, 
  however. She has clashed with the modrons of Regulus, 
  and sees the arrival of the Glass God as nothing more than 
  a nuisance. Her desire is to colonize the multiverse with 
  formians, thus making everything perfectly ordered and 
  working harmoniously together. Even if it’s against the will 
  of the people in the multiverse.
  Glass God
  Strange things have been seen appearing in Mechanus 
  recently. Some smaller cogs and gears have transformed 
  seemingly spontaneously from metal into strangely 
  prismatic clear glass. The gears continue to move in the 
  same way as they have before, and the sudden changes 
  haven’t prompted the modrons of Regulus to do anything 
  more than a cursory check – to their rigid minds, the gears 
  are functional and that’s all that matters.
  At the same time, devotees have appeared in the 
  Clockwork Nirvana claiming to speak for a new power 
  they call the Glass God. This being comes from outside 
  the plane of Mechanus but has a wonderful future planned 
  that incorporates everything great about Mechanus into a 
  new form. These devotees are accompanied by warriors 
  carrying strange glass weapons, along with more sinister 
  creatures known as glass hounds. Everything about the 
  Glass God as spoken about by these speakers and warriors 
  refers to a harmonious convergence of machine and glass.
  The truth is far more sinister, however. The Glass 
  God is an alien intelligence from the Far Realm who has 
  penetrated Mechanus and seeks now to convert the entire 
  plane into something different. The Glass God and its most 
  fervent followers, including the glass hounds, have strange 
  abilities to jump between sharp angles, which are plentiful 
  on Mechanus, and they can see things through the glass 
  gear spreading out across the Clockwork Nirvana. Sects 
  of warriors calling themselves glass eidolons have taken 
  up the arms of the Glass God, most not knowing the exact 
  nature of their mysterious patron, but the speakers and 
  devotees seem to be knowledgeable about the grander 
  scheme – assimilate, and destroy those that resist.
  Inevitables
  Constructs are prevalent in Mechanus, but there are 
  constructs that have evolved beyond the relatively 
  simplistic golems found across the multiverse. The 
  modrons are one type who have evolved to serve the will 
  of Primus and keep the Clockwork Nirvana ticking, but 
  there is another class of intelligent constructs in Mechanus 
  that enforce laws rather than simply maintaining them. 
  These are the inevitables, and though they appear at 
  first glace like golems, they are intelligent creatures with 
  hyper-focused wills all bent on enforcing laws across the 
  multiverse.
  The most commonly encountered type of inevitable 
  found outside of Mechanus are the marut, who dwell 
  within Halls of Concordance in several major planar 
  metropolises. These iron constructs are incredibly 
  powerful and built with the singular purpose of enforcing 
  the terms of a contract. It can be any contract agreed to 
  by separate parties at a Hall of Concordance. Each Hall of 
  Concordance is run by a Kolyarut, a specialized version of 
  the marut that arbitrates on behalf of the individuals and 
  assigns a marut to keep the terms of the agreement by all 
  parties.
  Maruts originate in massive factories on Mechanus. 
  Each factory is given a three digit number to differentiate 
  it from others, though the largest and most expansive is 
  Factory Zero-Zero-One, the first, where inevitables build 
  more inevitables in titanic life molds within the factory. 
  Other factories produce armor, weapons, and the internal 
  workings of the creatures, but Factory Zero-Zero-One puts 
  them all together and creates the form itself.
  Other types of inevitables exist as well. The hadrut are 
  less powerful than the maruts but still capable creatures 
  that are built on a larger scale. Their purpose is to enforce 
  borders, so they are often found around factories, and 
  many can be found around the Scrap Tracts in Mechanus 
  guarding against scavenger tribes. Other inevitables 
  enforce other laws of the multiverse, including the law of 
  death, the laws of time, and the laws of reality itself. These 
  other types are more rare but just as powerful as the 
  marut.
  The first inevitables were believed to be created by 
  Primus as a tool to enforce order in Mechanus. The 
  modrons have an enormous population but they are built 
  for maintaining the workings of the Clockwork Nirvana, 
  and even then they are too few to handle all of the plane’s 
  inner machinations. Primus needed something to bring 
  order to the wider planes, and the inevitables were the 
  result. The first inevitables quickly gained sentience and 
  started building more themselves – they were the ones that 
  constructed and now maintain the factories, not Primus, 
  though enigmatic logic being seems to approve of the 
  advancement.
  The Mathemagician
  Manipulating arcane energy to create magic requires 
  complicated rules and conditions. This is why wizards 
  have to devote so much time to study, and also why some 
  are tempted to make bargains with otherworldly powers 
  to circumvent that required work. The plane of Arcadia 
  contains Nomos Prime, a powerful enigmatic force that 
  most believe embodies these arcane laws, but there 
  is a competing force in Mechanus that is pushing the 
  boundaries of logic and magic to their utmost. This is 
  the Mathemagician, a constructed humanoid known as a 
  warforged, who has become an incredibly powerful wizard 
  driven insane by dabbling in the cosmic power of the 
  multiverse.
  The Mathemagician believes words are the key to 
  unlocking the laws of magic, and that those words 
  originated somewhere in Mechanus. It has built the Palace 
  of Perfect Precept on a distant cog where he is attended 
  by helmed horrors of its own creation. Few people visit the 
  
  Volume XXIII  |  Clockwork Nirvana of Mechanus
  7
  palace, and the Mathemagician seems perfectly content 
  with this, but the power that it wields has attracted some 
  attention. Specifically, nomomancers from Arcadia have 
  been studying the warforged wizard for some time, secretly 
  observing from a distance.
  For its part, the Mathemagician seems content to study 
  and experiment. The helmed horrors that assist it are a 
  useful addition to any wizard’s guardian arsenal, though 
  the secrets of their creation are jealously guarded by the 
  crazed warforged. The Mathemagician is completely 
  obsessed with law and how it applies to arcane magic, and 
  it has visited Primus in Regulus on numerous occasions, 
  though each time the warforged leaves with more 
  questions than answers. How close is the Mathemagician 
  to unlocking arcane secrets lost to the multiverse? How 
  much of a threat are those secrets? What are the true 
  motivations of Nomos Prime in regard to the warforged? 
  No one has these answers yet.
  Primus and the Modrons
  Order is a major defining force in the multiverse. It’s what 
  tamed the raw chaos of existence at the beginning of 
  everything into the structure of reality, and most planar 
  scholars agree that this lawful power is embodied wholly 
  in the singular being known as Primus. As an entity, 
  Primus is one of the oldest things in the multiverse, with 
  records dating back as far as records go detailing its 
  influence over the planes, just as Asmodeus has spread the 
  influence of evil and corruption.
  Primus sits at the literal center of Mechanus, at 
  least as defined by the modrons that serve it without 
  question. These geometrically-shaped creatures are 
  living constructs, similar to inevitables, but they are built 
  for maintaining the order of the Clockwork Nirvana and 
  keeping everything running smoothly. Their rigid hierarchy 
  prevents lesser modrons from even interacting with higher 
  modrons – they don’t even speak the same language. At 
  the top sits Primus, the being of pure law and order, who is 
  said to dwell within every cog and gear in Mechanus. The 
  Tower of Primus is at the center of Regulus, the realm of 
  the modrons, where it contemplates existence and watches 
  over the multiverse.
  As a being of pure law, devoid of good and evil, Primus 
  is difficult to understand at times. Its goal is to bring 
  ultimate order to the multiverse, and the tools it uses are 
  the modrons, but it also experiments from time to time. 
  Primus is responsible for several strange acts – it created 
  the stone that now sits in Limbo that created the slaadi, 
  for example, creatures of absolute chaos and destruction. 
  And, there are the occasional modrons that go “rogue” 
  and develop independent thoughts of their own. Some 
  say these are explicitly created by Primus as a way to test 
  its most loyal subjects. It’s a puzzling situation that has 
  interested planar sages for generations.
  It is said that Primus sees everything in Mechanus, and 
  can manifest in any gear or cog across the plane. This level 
  of planar control is nearly unheard of anywhere else in the 
  multiverse, suggesting Primus has a unique relationship 
  with the Clockwork Nirvana. But it rarely exercises this 
  power openly, preferring instead to set plans into motion 
  and then watch them unfold.
  Scavenger Tribes
  There are many small communities of creatures of all 
  kinds that live, work, and die in the cogs of Mechanus. 
  Most of these communities are built on a single gear, 
  and the residents – whether they be archons from Mount 
  Celestia, devils from the Nine Hells, or planar transplants 
  from across the multiverse – strive to stay in harmony 
  with their clockwork surroundings. Chaotic tendencies 
  are generally weeded out naturally, for few of a non-lawful 
  mindset can withstand the sheer enormity of order and 
  synchronization of Mechanus.
  The scavenger tribes are the exception, however. These 
  roving bands of anarchists, free thinkers, warriors, and 
  tinkers roam about the gears and cogs of the plane, 
  collecting scrap for their own use while staying one step 
  ahead of the modrons that continually chase them. Mainly 
  comprised of humanoids, the tribes are usually less than 
  50 people, as the smaller the number the more nimble 
  their movements, and the easier it is to escape from 
  modrons trying to shut down their activities.
  The members of the scavenger tribes call themselves 
  the gearlost, and they are quite adept at taking scraps from 
  the plane and turning them into useful pieces of mobile 
  equipment. They don’t make permanent settlements, but 
  they do meet irregularly on a cog called the Plain of the 
  Gearlost, near an abandoned Scrap Tract far from the 
  modrons’ home of Regulus. Tribal leaders meet here to 
  discuss new tactics from modrons, valuable yards for 
  scavenging, and any new hazards or dangers they face. 
  They aren’t inherently dangerous, but there’s a rebellious 
  streak in most of them that sees a great machine like 
  Mechanus and simply wants to tear it down.
  Many gearlost have replaced parts of their body with 
  mechanical bits, usually hands and legs but sometimes 
  as advanced as an eye or complete spine. The artificers 
  among the gearlost are adept at melding machine with 
  flesh, which the modrons and inevitables look upon 
  with great shock and horror. There is, however, no such 
  law against such a melding so possessing a gearlost 
  modification is not an automatic sentence for death. 
  Word of Law
  In the plane of ultimate law, ultimate justice is meted out 
  swiftly and without mercy, compassion, or malice. Primus 
  was the original arbiter of justice, but over time it created 
  another power to oversee passing sentences for those that 
  break the law in Mechanus. The Word of Law was born 
  from this, and from the Scriptorium of Law it hears cases 
  and swiftly deals justice.
  The Word of Law is a strange being. It is three massive 
  faces on a floating upside pyramid, with each side 
  representing a state of justice – passive, guilty, or innocent. 
  Its passive face is used while it hears cases, and then it 
  renders verdict by switching to its guilty or innocent face. 
  Inevitables of Mechanus work with the Word of Law but 
  its primary tool for handling criminals brought before it 
  are creatures of liquid living metal, silver or gold, known 
  as metal agents. Silver metal agents are the rank and file 
  servants of the Word of Law, and they are responsible 
  for guarding the Scriptorium of Law and watching over 
  
  Volume XXIII  |  Clockwork Nirvana of Mechanus
  8
  Buzzfly
  Small construct, unaligned
  Armor Class 16 (natural armor)
  Hit Points 33 (6d6+12)
  Speed 20 ft., fly 40 ft. (hover)
  STR
  DEX
  CON
  INT
  WIS
  CHA
  7 (-2)
  18 (+4)
  14 (+2)
  2 (-4)
  8 (-1)
  6 (-2)
  Damage Immunities acid, poison, psychic
  Condition Immunities charmed, exhaustion, frightened 
  poisoned
  Senses darkvision 60 ft., passive Perception 9
  Languages --
  Challenge 2 (450 XP)
  Flyby. The buzzfly doesn’t provoke an opportunity attack when 
  it flies out of an enemy’s reach.
  Magic Resistance. The buzzfly has advantage on saving throws 
  against spells and other magical effects.
  Actions
  Buzzsaw. Melee Weapon Attack: +6 to hit, reach 5 ft., one 
  target. Hit: 11 (2d6+4) slashing damage.
  Acid Spray (Recharge 5-6). The buzzfly sprays out a 15-foot 
  cone of acid. Creatures caught in the radius must make a DC 
  12 Dexterity saving throw, suffering 14 (4d6) acid damage on a 
  failure, or half as much on a success.
  prisoners. Gold metal agents are the ones that seek out 
  criminals in Mechanus, and some have even gone so far as 
  to travel beyond the Clockwork Nirvana in their duties.
  The punishment for breaking any law on Mechanus is 
  death, meted out swiftly and impartially by the Word of 
  Law’s silver metal agents once sentence has been passed. 
  The Word of Law is impartial and it hears cases clearly 
  without inherent bias or prejudgment. Nonetheless, 
  criminals brought before it at the Scriptorium of Law are 
  usually found guilty. In the alien mind of the Word of Law, 
  and by extension Primus, no lawbreaker can be allowed to 
  live, no matter the scale of the crime.
  Creatures & Denizens
  Constructs abound in Mechanus. Many are formed 
  naturally on the plane, while others – such as golems – are 
  created by deliberate action from inhabitants of the plane. 
  Many of the creatures of Mechanus have an absolute view 
  of law and order, regardless of good and evil, and see no 
  difference between a fiend breaking a law or an angel.
  Buzzfly
  One of the most common nuisance creatures in Mechanus 
  is the buzzfly. This creature resembles a large mechanical 
  fly, about the size of a dog, with delicate clockwork wings 
  and a wickedly spinning circular saw attached to its thorax. 
  They spray caustic acid from an opening at their mouth 
  that eats away at metal and flesh just as easily, allowing the 
  creature to lap up the sizzling remains. Buzzflies generate 
  a distinct buzzing sound that can be heard up to 100 feet 
  away, making them bad at stealthy approaches, but they 
  make up for it in sheer numbers and lethal acidic spray.
  Vermin of Mechanus. Mechanus doesn’t have a lot of 
  vermin found elsewhere in the multiverse, so the buzzfly 
  occupies this ecological niche. It eats gears and cogs 
  dissolved with its acid, requiring the modrons to constantly 
  follow the swarms to clean up, which also means the 
  buzzflies are responsible for the largest amount of refuse. 
  The scavenger tribes tend to follow the movement patterns 
  of the buzzfly swarms as well, keeping a low profile and 
  picking out the best junk before the modrons haul it away 
  to a Scrap Tract. The scavengers themselves have to watch 
  out, however, as the buzzflies have been known to attack 
  them just as quickly as the gears of Mechanus, especially 
  since many members have replaced their limbs with 
  moving mechanical parts.
  
  Volume XXIII  |  Clockwork Nirvana of Mechanus
  9
  Gearwraith
  Medium undead, lawful evil
  Armor Class 18 (natural armor)
  Hit Points 104 (16d8+32)
  Speed 0 ft., fly 50 ft. (hover)
  STR
  DEX
  CON
  INT
  WIS
  CHA
  19 (+4)
  13 (+1)
  15 (+2)
  11 (+0)
  15 (+2)
  17 (+3)
  Damage Resistances acid, cold, fire, lightning, thunder; 
  bludgeoning, piercing, and slashing from nonmagical 
  weapons that aren’t silvered
  Damage Immunities necrotic, poison
  Condition Immunities charmed, exhaustion, grappled, paralyzed, 
  petrified, poisoned, prone, restrained
  Senses truesight 60 ft., passive Perception 12
  Languages the languages it knew in life
  Challenge 7 (2,900 XP)
  Incorporeal Movement. The gearwraith can move through other 
  creatures and objects as if they were difficult terrain. It takes 5 
  (1d10) force damage if it ends its turn inside an object.
  Innate Spellcasting. The gearwraith’s spellcasting ability is 
  Charisma (spell save DC 14). It can innately cast the following 
  spells, requiring no material components.
  At will: heat metal, invisibility
  1/day: animate objects
  Metalbound. The gearwraith is clad in metal gears and cogs that 
  give it the equivalent of plate armor. Its tough metallic exterior 
  turns any critical hit against it into a normal hit.
  Actions
  Multiattack. The gearwraith makes two cogclaw attacks.
  Cogclaw. Melee Weapon Attack: +7 to hit, reach 5 ft., one 
  target. Hit: 13 (2d8+4) slashing damage plus 18 (4d8) psychic 
  damage.
  Gearwraith
  The grinding gears of Mechanus are dangerous to the 
  unwary. Creatures crushed by the cogs have a chance of 
  returning to life as a vengeful gearwraith, a spectral force 
  that seeks revenge on living creatures for having life it 
  was denied. They appear as they did in life except their 
  form is gray and insubstantial, though much of it is hidden 
  behind thick layers of gears that act as heavy armor. This 
  bulky outward appearance does nothing to lessen their 
  incorporeal movement, however, and they have an innate 
  ability to animate objects around them to harass and 
  destroy living targets.
  Enemies of the Gearlost. Many gearwraiths were 
  scavengers in life that got caught by the natural hazards of 
  Mechanus in their quest to dismantle the plane and turn it 
  into scrap. The Plain of the Gearlost, the meeting place for 
  many scavenger tribes across the Clockwork Nirvana, is 
  haunted by multiple gearwraiths, which must be expelled 
  or dealt with before any meeting can occur. The scavengers 
  have learned to lure gearwraiths away from the site by 
  asking for brave volunteers to lead them away; few survive 
  these dangerous assignments.
  Construct Avoidance. Gearwraiths focus their ire 
  and attention on living targets and normally ignore the 
  constructs that inhabit Mechanus. For their part, the 
  modrons and other natural inhabitants of the plane take no 
  notice of the gearwraiths as well. When a rogue modron 
  was presented with the question of why, it simply stated 
  that they didn’t view the spectral creatures as anything 
  more than a natural check on the non-native population.
  
  Volume XXIII  |  Clockwork Nirvana of Mechanus
  10
  Glass Hound
  Large aberration, lawful evil
  Armor Class 17 (natural armor)
  Hit Points 152 (16d10+64)
  Speed 50 ft.
  STR
  DEX
  CON
  INT
  WIS
  CHA
  22 (+6)
  14 (+2)
  19 (+4)
  19 (+4)
  12 (+1)
  9 (-1)
  Saving Throws Con +7, Int +7, Wis +4
  Skills Perception +7
  Damage Resistances bludgeoning, piercing, and slashing from 
  nonmagical weapons
  Damage Immunities force, psychic
  Condition Immunities charmed, exhaustion, paralyzed
  Senses truesight 120 ft., passive Perception 17
  Languages telepathy 120 ft.
  Challenge 10 (5,900 XP)
  Alien Mind. The glass hound has an abstract, alien mind. It can 
  concentrate on any number of spells at a time, though it must 
  make concentration checks under appropriate circumstance 
  for each one. Any attempt to read its thoughts or mind fails 
  automatically, and the creature attempting the action must 
  make a DC 15 Intelligence saving throw, suffering 36 (8d8) 
  psychic damage on a failure, or half as much on a success.
  Innate Spellcasting. The glass hound’s spellcasting ability is 
  Intelligence (spell save DC 15). The glass hound can innately 
  cast the following spells, requiring no material components:
  3/day each: far step, haste, slow
  Actions
  Multiattack. The glass hound makes two glass claw attacks.
  Glass Claw. Melee Weapon Attack: +9 to hit, reach 10 ft., 
  one target. Hit: 17 (2d10+6) slashing damage plus 18 (4d8) 
  psychic damage.
  Psychic Wave (Recharge 5-6). The glass hound releases a 
  wave of psychic energy. Living creatures in a 60-foot radius 
  must make a DC 15 Intelligence saving throw. If they fail, they 
  must choose to either suffer 36 (8d8) psychic damage or be 
  paralyzed until the end of the glass hound’s next turn.
  Glass Hound
  The recent arrival of the Glass God into the plane 
  of Mechanus has brought strange occurrences and 
  mysterious visitors to the ordered cog landscape. Some 
  entire gears have transformed completely from metal 
  into prismatic glass, retaining all of its former strength 
  but shining brighter than any other around it. The 
  modrons that maintain Mechanus don’t even seem to 
  notice the changes, but the scavenger tribes and many 
  other residents are more than a little worried. Glass-eyed 
  acolytes of the Glass God have been seen spreading a 
  word of harmony, but their peaceful words are undermined 
  by the fierce and savage glass hounds spotted around 
  them.
  Glass hounds are large quadruped creatures as big as 
  a dire wolf made entirely of prismatic glass. Their form 
  is made up of thousands of sharp angles, and in fact no 
  curved facet is found on their bodies. The head of a glass 
  hound is just as angular, largely triangular with seven 
  diamond-like eyes studded around its brow. It does not 
  speak, at least any language known to the multiverse, but 
  it can communicate via telepathy when it needs. It rarely 
  does so, however, choosing instead the silent stalk of a 
  predator.
  Not From Around Here. Since they first arrived in 
  Mechanus, planar scholars and wizards have tried to study 
  the glass hounds to learn more about where they came 
  from and how they’re connected to the strange Glass God. 
  Initial attempts at reading their minds resulted in blasted 
  psyches and stupefied bodies. The few images gleaned, 
  and by cross referencing with other details, leads most to 
  believe glass hounds originate from the Far Realm, in a 
  place referred to as Tindalos. 
  Angles of Space. Glass hounds can jump magically 
  between the angles around them, stepping into one and 
  reappearing in another as a form of teleportation. They 
  seem repelled by spheres and curved spaces, which are 
  not common in Mechanus, the plane of gears and cogs. It 
  has been theorized that a glass hound could be captured if 
  kept in a large sphere but so far none have been successful 
  at the attempt. The creatures are cunning and intelligent 
  in alien ways, making them dangerous foes who recognize 
  traps 
  
  Volume XXIII  |  Clockwork Nirvana of Mechanus
  11
  Clockwork Golem
  Medium construct, lawful neutral
  Armor Class 17 (leather armor)
  Hit Points 32 (5d8+10)
  Speed 30 ft.
  STR
  DEX
  CON
  INT
  WIS
  CHA
  15 (+2)
  8 (-1)
  15 (+2)
  6 (-2)
  10 (+0)
  1 (-5)
  Damage Resistances bludgeoning, piercing, and slashing from 
  nonmagical weapons
  Damage Immunities acid, poison, psychic
  Condition Immunities blinded, charmed, exhaustion, frightened, 
  paralyzed, petrified, poisoned
  Senses darkvision 60 ft., passive Perception 10
  Languages understands Common but can’t speak
  Challenge 2 (450 XP)
  Death Burst. When the golem dies, it explodes in a burst of 
  broken machinery. Each creature within 5 feet of it must make a 
  DC 13 Dexterity saving throw, taking 14 (4d6) slashing damage 
  on a failed save, or half as much on a successful one.
  Immutable Form. The golem is immune to any spell or effect 
  that would alter its form.
  Magic Resistance. The golem has advantage on saving throws 
  against spells and other magical effects.
  Precision Strike. The golem has advantage on its first attack in 
  a round.
  Actions
  Multiattack. The golem makes two slam attacks.
  Slam. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. 
  Hit: 7 (1d10+2) slashing damage.
  Golem, Clockwork
  Golems of all kind can be found in the Clockwork Nirvana 
  of Mechanus. Some are the guardians of communities, 
  some are seekers on a mission, and some are just lost 
  among the gears, wandering with no other purpose than to 
  wander. The most frequently encountered type of construct 
  is the clockwork golem, which are created and used by 
  the members of the Confederacy of the Cog. The artificers 
  there have perfected the mass production of clockwork 
  golems and treat them like expendable servants. They 
  usually appear as humanoids constructed entirely out of 
  moving gears, pistons, and cogs, like the inner working 
  of a clock. Any eyes or facial expressions are purely 
  for decoration as the golem needs neither to sense its 
  surroundings.
  Legions of the Cog Confederacy. Clockwork golems 
  are built primarily by the artificers of the Confederacy 
  of the Cog in their splendid Transcendent Academy. It is 
  considered a point of pride for each member to build their 
  own clockwork golem, if nothing more than to prove their 
  skill to their fellows, though the constructs are handy to 
  have around in a lab. In the rare times the Confederacy 
  must take military action against some force, such as when 
  a spurned artificer turned rogue, the clockwork golems are 
  marshalled and sent to do battle on behalf of the academy.
  Construction Secrets. Transcendent Academy records 
  indicate that the first clockwork golem was actually a 
  gift from Primus to the artificers that first formed the 
  Confederacy of the Cog. It came with well-wishes and a 
  warning that the constructs were not be abused or taken 
  advantage of lest the artificers risk an uprising. The words 
  were enough to scare the first few generations, but over 
  time most believed Primus was merely being poetic. Each 
  clockwork golem is the creation of the personal artificer 
  and they all go through rigorous inspection for flaws or 
  irregularities. None have been found, so surely the golems 
  are just the mindless creations they seem to be.
  
  Volume XXIII  |  Clockwork Nirvana of Mechanus
  12
  Inevitable
  The inevitables are intelligent constructs built originally 
  by Primus to fulfill specific duties around the relationships 
  Mechanus needed to establish with outside creatures. 
  Each type of inevitable is created with a singular purpose 
  around enforcing Mechanus’ laws across the multiverse. 
  Inevitables vary in appearance by type, but they appear 
  generally as elaborate golems, incorporating metal, gears, 
  stone, and more in their striking designs.
  Factory Born. After their initial creation, the inevitables 
  realized they would need more of their kind in order to 
  enforce their chosen laws. Factories were constructed in 
  Mechanus, but the intelligent constructs tried to break up 
  the work done by each to minimize their weakness – if 
  one factory were to be destroyed, it would be simply one 
  step in the larger process. The most important is the first 
  one, Factory Zero-Zero-One, where the life molds for the 
  inevitables are kept and the actual spark of life is given into 
  each. It is heavily guarded and its location is kept a secret 
  from outsiders.
  Active Outside of Mechanus. The task of each 
  inevitable is to enforce a particular law of the multiverse 
  as laid out by Primus. The marut are the most visible to 
  outsiders as these powerful creatures enforce contracts 
  signed in the Halls of Concordance in major planar 
  metropolises, and they are nearly unstoppable in fulfilling 
  their missions. Liches and other undead that push the 
  limits of their power too far may get a visit from an 
  inevitable that enforces the laws of death, while those 
  that tamper with time itself may find themselves facing off 
  against more powerful inevitables.
  Hadrut
  The hadrut are a lesser type of inevitable charged with 
  protecting borders and securing specific locations around 
  the laws of property. They resemble beardless mechanical 
  dwarves, with squat bodies and heavy fists, and like most 
  inevitables they are intelligent though lack imagination. 
  Powerful beings can request the protection of hadrut by 
  appealing to Primus directly, but they were originally built 
  by other inevitables to protect their factories and other 
  sites of interest on Mechanus. Legions of them are used to 
  keep the Scrap Tracts safe from outsiders.
  Hadrut
  Medium construct (inevitable), lawful neutral
  Armor Class 18 (natural armor)
  Hit Points 84 (8d10+40)
  Speed 40 ft.
  STR
  DEX
  CON
  INT
  WIS
  CHA
  19 (+4)
  10 (+0)
  20 (+5)
  17 (+3)
  14 (+2)
  15 (+2)
  Skills Insight +4, Perception +4
  Damage Resistances thunder; bludgeoning, piercing, and 
  slashing from nonmagical weapons
  Damage Immunities poison
  Condition Immunities charmed, frightened, paralyzed, poisoned, 
  unconscious
  Senses darkvision 60 ft., passive Perception 14
  Languages all
  Challenge 4 (1,100 XP)
  Immutable Form. The inevitable is immune to any spell or effect 
  that would alter its form.
  Innate Spellcasting. The inevitable’s innate spellcasting ability is 
  Intelligence (spell save DC 13). The inevitable can innately cast 
  the following spells, requiring no material components:
  At will: command, hold person
  1/day: hold monster
  Magic Resistance. The inevitable has advantage on saving 
  throws against spells and other magical effects.
  Actions
  Multiattack. The inevitable makes two slam attacks.
  Slam. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. 
  Hit: 9 (1d10+4) bludgeoning damage.
  
  Volume XXIII  |  Clockwork Nirvana of Mechanus
  13
  Metal Agent
  Justice on Mechanus is handed out by a powerful force 
  known as the Word of Law, in a grand courtroom in the 
  Scriptorium of Law. This being is fairly immobile, so it 
  must have others do the actual work of bringing criminals 
  to the Scriptorium and then carrying out the sentence. 
  These duties fall to the metal agents, constructs of 
  living metal that resemble oozes more than traditional 
  constructs. There are two castes of metal agents, silver 
  and gold, but beyond their base metallic color they are 
  fairly similar. A metal agent’s natural form is a large puddle 
  of liquid metal, but it can form itself into any shape it 
  desires. Its hands elongate and can transform into any 
  weapon, though the gold metal agents have the added 
  ability of infusing their attacks with energy, and both types 
  require neither food nor drink to sustain themselves.
  Agents of Supreme Law. Metal agents are imbued with 
  the knowledge of Mechanus’ laws by the Word of Law 
  itself, and the silver metal agents are often sent out into 
  the plane to apprehend lawbreakers and criminals and 
  return them to the Scriptorium of Law. Gold metal agents 
  rarely leave the Scriptorium as their prime responsibility 
  is carrying out the sentences of the guilty, which is death in 
  most cases.
  Trials Without Passion or Mercy. The Word of 
  Law oversees trials in the Scriptorium of Law that are 
  inherently without bias, passion, or mercy, and the 
  verdicts are rendered quickly in most cases. Gold metal 
  agents are on hand at every trial to swiftly carry out the 
  sentence of death as lawbreakers cannot be allowed to 
  live, while silver metal agents watch over the imprisoned. 
  Defendants before the Word of Law are allowed to argue 
  their own case in an attempt to sway the verdict in their 
  favor, but this rarely works – the Word of Law has supreme 
  knowledge of all laws on Mechanus and it views things in 
  black and white. A law is broken and thus the lawbreaker 
  must be punished. Gold and silver metal agents carry the 
  same dispassionate fervor for justice as their patron and 
  they can rarely be swayed from carrying out their duties.
  Gold Metal Agent
  Medium construct, lawful neutral
  Armor Class 19 (natural armor)
  Hit Points 150 (20d8+60)
  Speed 50 ft.
  STR
  DEX
  CON
  INT
  WIS
  CHA
  15 (+2)
  24 (+7)
  17 (+3)
  19 (+4)
  12 (+1)
  10 (+0)
  Damage Resistances bludgeoning, piercing, slashing
  Damage Immunities fire, lightning, necrotic, poison, psychic, 
  radiant
  Condition Immunities blinded, charmed, deafened, exhaustion, 
  frightened, grappled, poisoned, prone, restrained
  Senses blindsight 120 ft., passive Perception 11
  Languages all
  Challenge 10 (5,900 XP)
  Amorphous. The metal agent can move through a space as 
  narrow as 1 inch wide without squeezing.
  Cold Reaction. If the metal agent is subjected to cold damage it 
  acts as if under the slow spell until the end of its next turn.
  Magic Resistance. The metal agent has advantage on saving 
  throws against spells and other magical effects.
  Quick. The metal agent is surprisingly fast and takes an extra 
  action each round. The extra action can be used only to take the 
  Attack (one weapon attack only), Dash, Disengage, Hide, or Use 
  an Object action.
  Weapon Reform. As a bonus action the metal agent can 
  change the damage type of its slam attack to bludgeoning, fire, 
  lightning, piercing, psychic, or slashing.
  Actions
  Multiattack. The metal agent makes two slam attacks.
  Slam. Melee Weapon Attack: +11 to hit, reach 10 ft., one target. 
  Hit: 23 (3d10+7) bludgeoning damage.
  Silver Metal Agent
  Medium construct, lawful neutral
  Armor Class 16 (natural armor)
  Hit Points 90 (12d8+36)
  Speed 50 ft.
  STR
  DEX
  CON
  INT
  WIS
  CHA
  15 (+2)
  20 (+5)
  17 (+3)
  15 (+2)
  12 (+1)
  10 (+0)
  Damage Resistances bludgeoning, piercing, slashing
  Damage Immunities fire, lightning, necrotic, poison, psychic, 
  radiant
  Condition Immunities blinded, charmed, deafened, exhaustion, 
  frightened, grappled, poisoned, prone, restrained
  Senses blindsight 120 ft., passive Perception 11
  Languages all
  Challenge 6 (2,300 XP)
  Amorphous. The metal agent can move through a space as 
  narrow as 1 inch wide without squeezing.
  Cold Reaction. If the metal agent is subjected to cold damage it 
  acts as if under the slow spell until the end of its next turn.
  Magic Resistance. The metal agent has advantage on saving 
  throws against spells and other magical effects.
  Quick. The metal agent is surprisingly fast and takes an extra 
  action each round. The extra action can be used only to take the 
  Attack (one weapon attack only), Dash, Disengage, Hide, or Use 
  an Object action.
  Weapon Reform. As a bonus action the metal agent can change 
  the damage type of its slam attack to bludgeoning, piercing, or 
  slashing.
  Actions
  Multiattack. The metal agent makes two slam attacks.
  Slam. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. 
  Hit: 16 (2d10+5) bludgeoning damage.
  
  Volume XXIII  |  Clockwork Nirvana of Mechanus
  14
  Oil Jelly
  The gears of Mechanus are in constant motion, grinding 
  into one in another in never-ending movement. At least, 
  that’s the idea, but sometimes the gears and cogs freeze 
  up, and when this happens the modrons that tend to the 
  vast machinery of the plane work to lubricate the gears 
  so that they move freely again. Most of this lubrication 
  comes from large lakes of slick black oil located around 
  Mechanus, and in some of those the oil has taken on a life 
  of its own. Oil jellies are semi-sentient oozes birthed in 
  unknown conditions within the oil lakes, and they appear 
  as large patches of shiny black liquid. They slither with 
  surprising speed and fight against the modrons to preserve 
  their oily homes.
  Accident or Design? The nature of the oil jellies suggest 
  a spontaneous creation birthed by accident and chance 
  rather than deliberate design, but that would go against 
  the basic principles of Mechanus. The philosophical 
  conundrum has vexed planar scholars for generations, 
  who mostly have come to the conclusion that Primus is 
  responsible for the oil jellies and there is a pattern to their 
  creation. The pattern is simply not visible to mortals.
  Oil Jelly
  Large ooze, unaligned
  Armor Class 8
  Hit Points 76 (8d10+32)
  Speed 40 ft., climb 40 ft.
  STR
  DEX
  CON
  INT
  WIS
  CHA
  16 (+3)
  7 (-2)
  19 (+4)
  2 (-4)
  6 (-2)
  1 (-5)
  Damage Immunities acid, fire, lightning, slashing
  Condition Immunities blinded, charmed, deafened, exhaustion, 
  frightened, grappled, prone
  Senses blindsight 60 ft. (blind beyond this radius), passive 
  Perception 8
  Languages --
  Challenge 3 (700 XP)
  Flammable. If the jelly is subjected to fire damage it catches 
  fire. While it is on fire, any creature in the same space as the 
  jelly suffers 14 (4d6) fire damage at the beginning of the jelly’s 
  turn. The jelly remains on fire for 1 minute.
  Slick Form. The jelly can enter a hostile creature’s space and 
  stop there. It can move through a space as narrow as 1 inch 
  wide without squeezing. Creatures that start their turn in the 
  same space as the jelly must make a DC 13 Dexterity saving 
  throw or fall prone.
  Actions
  Multiattack. The jelly makes two pseudopod attacks.
  Pseudopod. Melee Weapon Attack: +5 to hit, reach 5 ft., one 
  target. Hit: 8 (1d10+3) bludgeoning damage. The target must 
  succeed on a DC 13 Dexterity saving throw or fall prone.
  
  Volume XXIII  |  Clockwork Nirvana of Mechanus
  15
  Hazards & Phenomena
  The great machine of Mechanus is a vast, moving 
  plane of interconnected gears and cogs, all ticking in 
  synchronization, like the inner workings of a massive 
  water clock. The operations are so enormous in scale that 
  they create unique environments not found anywhere else 
  in the multiverse, at least on the same scale. Travelers 
  to Mechanus quickly become aware of these factors as 
  they affect everything from communication to combat 
  effectiveness.
  Great Modron March
  One of the strangest phenomena of Mechanus is the Great 
  Modron March. Once every 289 years, Primus orders the 
  modrons of Regulus to march across the multiverse. They 
  leave the Clockwork Nirvana and navigate the planes, 
  traveling along well-established routes that use gates and 
  portals to cross between the planar borders.
  The Great Modron March is a massive operation, with 
  thousands of modrons marching, and their path never 
  wavers, regardless of the obstacles. Cities may have sprung 
  up since the last march, or natural hazards or barriers, 
  but none of that stops the single-minded modrons from 
  their task. Some difficulties require construction to bypass, 
  which are handled by specific modrons, and include things 
  like building bridges, repairing gates, and removing hostile 
  forces. Unfortunately, the modrons are not especially 
  skilled at this last part, and many that go out on the march 
  do not return to Mechanus.
  There are several lesser marches that happen between 
  each Great Modron March where Primus sends out 
  smaller teams of modrons to venture forth to a series of 
  specific planes. These lesser marches occur in regular 
  patterns, like everything the modrons do, but the scale is 
  difficult for outsiders to comprehend.
  Why does Primus send modrons out on these marches? 
  The question has baffled planar sages for generations. 
  Most assume it’s some sort of checkup on the state of the 
  multiverse, a kind of update to a larger plan known only 
  to Primus, but there are conspiracy theories that suggest 
  a more sinister motivation. It is well known that Primus’ 
  goal is to bring absolute law and order to the multiverse, 
  and the modrons are its most successful tool to date in this 
  effort. Do the modrons march to test the defenses of the 
  multiverse in advance of some predetermined war for total 
  domination? Or perhaps they march to charge up some 
  force or power within Mechanus and they wait for the right 
  time to unleash it?
  Grinding Gears
  Mechanus is in constant motion, and the gears and cogs 
  that make up the bulk of the plane move by connecting 
  precise interlocking teeth. It’s a ballet of motion, but it can 
  also be dangerous if a person were to be caught in the 
  gears.
  Gear sizes in Mechanus come in five broad categories – 
  small, medium, large, huge, and gargantuan. While these 
  sizes correspond to creature sizes, the gear sizes are on a 
  much larger scale. Getting caught in the interlocking teeth 
  of a gear inflicts bludgeoning damage based on the size 
  of the gear. The chart below shows the relative size and 
  damage.
  Category
  gear Size
  Bludgeoning 
  damage
  Small
  Up to 5 feet diameter
  7 (2d6)
  Medium
  From 5 to 100 feet 
  diameter
  17 (5d6)
  Large
  From 100 feet to 1 mile 
  diaemter
  35 (10d6)
  Huge
  From 1 mile to 50 mile 
  diameter
  52 (15d6)
  Gargantuan
  50 mile or more diameter
  70 (20d6)
  Creatures must be close to a gear’s edge for any damage 
  to occur, and even then the relative gravity of Mechanus 
  makes falling into it unlikely. It is possible to shove a 
  creature into a gear which would then inflict the listed 
  bludgeoning damage. Gear damage is based on the size of 
  the adjoining gear, which can be up to one size category 
  bigger or smaller than the primary gear.
  For example, if a group of adventurers were facing off 
  against a foe near the edge of a large gear, the DM could 
  determine an adjacent grinding gear was medium, large, or 
  huge, and if a creature were to be shoved into the gear they 
  would suffer bludgeoning damage based on that adjacent 
  gear’s size. It’s worth noting that modrons never think 
  of pushing creatures into the gears – there’s a chance, 
  however remote, that the gear could get stuck, and so this 
  tactic is strictly forbidden by the modrons.
  Law of Averages
  Mechanus runs on an edict of well-defined structure and 
  order. Randomness is reduced and chaos is kept to a 
  minimum, or eliminated entirely. Creatures that engage in 
  combat on Mechanus quickly find their attacks and spells 
  create predictable effects regardless of luck and timing. 
  While on Mechanus, all creatures use the average damage 
  for spells and weapon attacks. The average damage on 
  a die is reflected as half of the die’s maximum value plus 
  0.5, though rounding always occurs down. For example, a 
  longsword inflicts 1d8 damage, so the average would be 
  4.5, round down to 4. A greatsword inflicts 2d6 damage, 
  so the average would be 7 (3.5 x 2). Apply modifiers as 
  normal.
  
  Volume XXIII  |  Clockwork Nirvana of Mechanus
  16
  Linguistic Equality
  Communication can be a barrier on any plane, but on 
  Mechanus the language laws are broken down intrinsically 
  to their base values to facilitate easy understanding. 
  Regardless of the languages spoken, while on Mechanus 
  all creatures can understand the spoken words of other 
  creatures as if it were a language they could speak. There 
  is no inherent ambiguity in this instant translation and 
  most creatures don’t even realize it’s happening because of 
  its subtle effect.
  Mysterious Sites & Treasures
  The Clockwork Nirvana of Mechanus is filled with 
  wondrous sites that simply cannot be replicated anywhere 
  else in the multiverse. Some of them are dangerous, some 
  are beautiful, but all are part of the massive machine that 
  makes up the plane and its coordinated synchronization.
  Cogmaze
  The vast majority of Mechanus is filled with gears and 
  cogs of an enormous scale, many stretching hundreds of 
  miles across. Regions overhead and below are just as filled 
  with gears, but there is an openness to the spacing that 
  can create an illusion of emptiness. In the region known 
  as the Cogmaze, however, this illusion is dispelled as the 
  individual gears are close enough together to form walls, 
  corridors, and rooms.
  The Cogmaze is a complicated region that spans several 
  miles of tightly compounded small gears, moving and 
  grinding at variable speeds. It isn’t known if the site is a 
  naturally occurring phenomena, or if it was deliberately 
  created to house something specific or dangerous. 
  Creatures have been found in the Cogmaze, usually 
  variations of the clockwork golems, buzzflies, and other 
  natural inhabitants of Mechanus, but there is a sinister 
  undercurrent to the monsters that differentiates them from 
  their wild fellows. Modrons have an irrational fear of the 
  Cogmaze with most refusing to go near it, though they 
  can’t say why – they simply say it is a decree from a higher 
  authority.
  Adventurers that have gone into the Cogmaze report 
  encounters with insidious traps and clockwork monsters 
  that seem to exist only within the grinding corridors. 
  Treasure too has been found, strange mechanical devices 
  of a mystic and wondrous nature, almost as if something 
  were using the Cogmaze to store precious items – or 
  to lure in unsuspecting adventurers. What lurks in 
  the heart of the Cogmaze? Is there a greater power 
  behind its construction, or does it house scavengers and 
  opportunistic creatures looking for a new home?
  Crimson Clock
  For a plane known as the Clockwork Nirvana, there is a 
  surprising lack of actual clocks around Mechanus. The 
  modrons that maintain the gears and cogs of the plane 
  don’t need them, as they are in tune with the plane itself, 
  and many of the local communities learn to tell time by 
  the chiming of the Nirvana Bells and movement of nearby 
  gears. One of the few actual time pieces on Mechanus is a 
  massive red obelisk known as the Crimson Clock, which is 
  tended by cultists of Asmodeus, the Lord of the Nine Hells.
  As a supreme power in the multiverse, Asmodeus has a 
  vested interest in the inner workings of Mechanus, and he 
  seems as interested in discovering the ultimate purpose of 
  the plane as any planar scholar. To that end, the Crimson 
  Clock was built on a red-stained gear, constructed by 
  specially created golems imbued with Asmodeus’ infernal 
  powers and magically linked to the machinations of 
  Mechanus. The result is a complicated clock that requires 
  constant tending by red-robed cultists, who have taken no 
  ill action against other planar inhabitants. The modrons 
  leave them alone since they aren’t breaking any laws, and 
  the Crimson Clock continues to tick.
  The clock itself records the passage of time, which is 
  meticulously tracked by the attendant cultists, but it also 
  has a countdown feature that was not originally planned. 
  None of the cultists know the end result of the countdown, 
  and their inquiries to Asmodeus have been met with 
  silence. The Crimson Clock has a vast inner working that 
  the cultists and a legion of chosen devil work to maintain, 
  but there are secret workings that most of them are not 
  aware of. Is it a doomsday clock that counts down to some 
  great calamitous event?
  Glass Spire
  The Glass God is an alien entity from the Far Realm 
  that has found a crack between the greater dimensional 
  barriers and is now slowly leaking into Mechanus. It is 
  a vastly malevolent entity bent on the total corruption 
  of the plane, a subjugation that would be manifested as 
  everything on the plane transforms into glass-like versions 
  of their original shape. Already, some cogs on Mechanus 
  have transformed into glass, and the modrons responsible 
  for repairing and maintaining the machinery seem not to 
  notice the difference.
  The transformative spread doesn’t seem to be localized 
  in any specific region on Mechanus, but the Glass God’s 
  greatest stronghold is the Glass Spire, a spike of strange 
  glass growing out of the middle of a great glassy gear. It is 
  here that the glass hounds congregate in larger numbers, 
  and the devotees of the Glass God – strange multicolored 
  eyed humanoids of persuasive tongue and purpose – 
  undergo ritualistic changes to become more in tune with 
  their supreme entity. The Glass God itself doesn’t seem to 
  have a physical presence in Mechanus, not yet at least, but 
  it’s unfathomable power is on display in around the Glass 
  Spire.
  The multi-tiered interior holds corridors, halls, 
  chambers, and room, all constructed of the same strange 
  prismatic glass as the spire and gear around it. Everything 
  is sharp angles, and some of those angles defy easy logic, a 
  clear violation of Mechanus’ natural laws. But the Word of 
  Law and its metal agents has not moved against the Glass 
  God yet. Is there something in the Glass Spire that shields 
  their lawlessness from the eyes of the plane? Primus has 
  been strangely silent on the appearance of the entity and 
  the site as well. How far does the glassification have to 
  spread before the powers of Mechanus take note?
  
  Volume XXIII  |  Clockwork Nirvana of Mechanus
  17
  Hive-City Arkitan
  Formians are an ant-like race of rigid structure and 
  supreme hierarchy. Everything they do is for the 
  betterment of their hive with no thought to the individual. 
  The sole exception is the individual at the top of each hive, 
  the queen, who directs the drones, soldiers, and others in 
  an ever-expanding quest for territory. Hives can be found 
  all across Mechanus, but the greatest is the central hive-
  city of Arkitan, home to the Scion Queen Mother.
  Arkitan is a massive complex built around a mile-high 
  tower, all of it constructed of hardened metal-like mud 
  produced by the drones by dissolving natural food and 
  transforming it into construction material. The result is 
  as strong as steel with a natural cave-like structure, and 
  Arkitan is the largest of all the hive-cities on Mechanus. 
  The Scion Queen Mother dwells in a massive central cave 
  at the tower’s base, attended by a legion of queenguards 
  and soldiers, and she has swarms of flying formians that 
  communicate with the other hives.
  Arkitan is highly organized, with all of the formians 
  inside operating according to the whim of the Scion Queen 
  Mother. They live, work, and die with no other thought than 
  for their queen, which is true of all formians, but the ones 
  in Arkitan are even more fanatically loyal. Arkitan formians 
  take no prisoners in warfare, fighting to the death in every 
  conflict, and voluntarily give their lives for the good of the 
  hive. And the Scion Queen Mother takes full advantage 
  of this force at her beck and call, and she has a plan to 
  expand the formian power across Mechanus – and into the 
  wider multiverse.
  Within the great spire of Arkitan, specialized drones 
  produce a magical secretion that the Scion Queen 
  Mother hopes will accelerate her expansionistic plans 
  dramatically. It’s kept under tight security now but some of 
  the scavenger tribes, who clash regularly with the formians 
  over scrap, have been subjected to its use - a powerful 
  mind-control vapor distilled from formian essence. To 
  date, the incidents have resulted in madness and death but 
  the formians working on perfecting the formula and the 
  Scion Queen Mother are not dismayed. The end results far 
  outweigh the potential cost in non-formian life it takes to 
  get there, or so they believe logically.
  Life Molds of Factory Zero-Zero-
  One
  Inevitable factories are located all across Mechanus. 
  Each one is assigned a three-digit identification number 
  and a specific task in the creation of more inevitables, 
  from Factory Two-Seven-Two where the eyes are created 
  to Factory Nine-Three-Four where cloaks are stitched 
  together. It is possible there are 999 factories, though they 
  all dwarf in importance to Factory Zero-Zero-One, where 
  final assembly is completed and the inevitables are given 
  the spark that turns them into creatures rather than simple 
  machines.
  Factory Zero-Zero-One was the first assembly plant built 
  by the inevitables to create more inevitables, and it houses 
  the supremely important life molds that are key to the 
  entire process. There are 10 known molds for each type of 
  inevitable, all housed in Factory Zero-Zero-One, and kept 
  under the tightest security to prevent tampering or even 
  close inspection. Non-inevitables are simply forbidden 
  from entering the factory under penalty of death.
  The factory is run by inevitables who take shifts 
  operating and guarding the facility, along with the other 
  factories that assemble the individual components. Parts 
  are shipped between each location in the great assembly 
  line, and during transport the crates are heavily guarded 
  and watched over closely. There have been some incidents 
  with scavenger tribes hijacking an inevitable shipment, 
  but the powerful constructs usually deal personally with 
  seeking out punishment rather than waiting for the metal 
  agents of the Word of Law to come in. Primus decreed that 
  the inevitables would have the ability to govern and police 
  themselves outside the typical Mechanus power structure.
  And there are plenty of interested parties in the 
  multiverse that would love to get a hold of the secrets 
  contained within any inevitable factory, but Factory 
  Zero-Zero-One is the motherlode. No one outside of the 
  inevitables knows the details of the spark that imbues 
  them with life and sentience, a power normally reserved 
  for gods, so to able to harness and control that power is 
  the dream of many beings and organizations, good and 
  evil.
  Magnetic Obelisks
  Traveling Mechanus is straightforward, because the risk 
  of falling off of a gear is low thanks to the relative gravity 
  each cog holds. Navigating and finding a specific place, 
  however, is a different matter entirely. The modrons have 
  their own grid-based system that maps out the entire plane 
  relative to Regulus, their realm and home of Primus, and 
  they maintain the grid through carefully placed magnetic 
  obelisks all around the Clockwork Nirvana.
  Each magnetic obelisk appears as a rectangular block 
  of glossy smooth black stone, exactly 10 feet high, 5 feet 
  wide, and 5 feet deep. They each hum with electrical 
  power as the inherent magnetism contained within each 
  vibrates on a high frequency, and metal objects brought 
  within 100 feet of a magnetic obelisk are drawn towards it 
  inexorably. Creatures holding a metal object and resisting 
  the pull must succeed on a DC 15 Strength saving throw 
  each round or be pulled 10 feet closer to the obelisk; metal 
  armor wearers suffer disadvantage on the saving throw 
  as they fight against their worn gear. Modrons know the 
  location of each obelisk and only approach within 100 
  feet by wearing special gem-studded belts that produce an 
  opposite magnetic charge to counteract the pull.
  Scavenger tribes wearing and carrying no armor have 
  managed to chip away pieces of magnetic obelisks, which 
  they use in their hunt for valuable junk in the various 
  Scrap Tracts around Mechanus. They’ve learned important 
  information about which types of scrap are attracted to 
  what size magnetic obelisk shard and at what range, so 
  they use it to quickly find the pieces that are the most 
  valuable to them. Modrons are concerned about the 
  destruction to the magnetic obelisks as it throws off their 
  navigation and the entire grid becomes unstable, though 
  their emotions are largely flat on the matter (as they are 
  with most things).
  
  Volume XXIII  |  Clockwork Nirvana of Mechanus
  18
  Nirvana Bells
  Mechanus is a noisy plane, with countless gears grinding 
  into one another on a constant basis. In many areas, the 
  sounds are synchronized, creating a natural cadence, but 
  just as often the sounds are drowned out by the sheer 
  volume. Residents get used to it, but it can be a bit of 
  a shock for travelers who have to shout to be heard in 
  some sections. What’s never drowned out, anywhere on 
  Mechanus, are the clear ringing of the Nirvana Bells that 
  chime every eight hours.
  Each Nirvana Bell is housed in a special open-framed 
  cube, about 20 feet tall, and the bells themselves are nearly 
  as grand. They are constructed of highly polished gold 
  inlaid with intricate patterns of gears and cogs in delicate 
  silver etchings. The golden clapper inside is motionless 
  and immobile under normal circumstances – no known 
  force can ring a Nirvana Bell outside the appointed time. 
  They ring out to signal the cycle of time on Mechanus, one 
  ring to start the day, two rings to bring in morning, and 
  three rings to herald evening.
  The modrons tend to the Nirvana Bells, polishing them 
  and keeping them in good physical condition, but they 
  do not ring them. No one has ever been observed ringing 
  them – they simply ring at the appointed time. Most planar 
  scholars believe they are in time with the running of the 
  plane itself, and therefore an extension of Primus, though 
  there is no evidence beyond conjecture to support this 
  theory. Cryptic prophecies across the multiverse refer to 
  disruptions in the ringing of the Nirvana Bells but there 
  are no recorded incidents of a change in their timing or 
  tone.
  Oil Lakes
  Modrons keep the gears of Mechanus moving by tending to 
  the cogs and cylinders that are in constant motion. Their 
  greatest tool in this regular upkeep is oil, fetched from 
  enormous lakes in a region close to Regulus, and then 
  distributed in special dispersing cans by modron oil teams. 
  These oil lakes sit in stacks of gears that have had their 
  centers removed, creating deep wells that replenish on 
  their own power.
  Oil jellies are a regular problem in these lakes, though 
  their exact origin isn’t known. It’s not likely they came into 
  being accidentally on a plane where everything happens 
  according to a plan, but no one has found a plan for the 
  oil jellies that makes any sense. Modron teams have to be 
  on the lookout for the dangerous oozes, and some of the 
  slimy creatures have learned to seek out sources of fire 
  and return to the oil lakes to deter further removal of the 
  precious liquid.
  Orrery of the Infinite Planes
  Regulus contains exactly 64 massive gears, all populated 
  by modrons of all types, but the center of their realm 
  consists of two buildings. One is the Tower of Primus, 
  wherein dwells the physical manifestation of the orderly 
  god, and the other is the Great Modron Cathedral, 
  standing next to Primus’ dwelling on the central cog of 
  Regulus. The Great Modron Cathedral sees visitors from 
  all across the multiverse who are welcomed as long as they 
  come peacefully to see a fantastic artifact – the Orrery of 
  the Infinite Planes.
  Housed in the central dome of the Great Modron 
  Cathedral, the Orrery of the Infinite Planes is a mechanical 
  model of the planes themselves, spinning and moving 
  around in perfect synchronization with each other. It’s a 
  working model of the multiverse, miniscule in scale but 
  still covering hundreds of feet in the cathedral’s massive 
  dome, and it is widely believed to be the only functional 
  “map” of all the Inner and Outer Planes. Scholars come 
  to study the patterns and movements, with the aid of 
  specialized modron workers who tend to the orrery’s 
  upkeep, though the great artifact set rarely requires any 
  maintenance.
  The Orrery of the Infinite Planes is useful for visualizing 
  the relationship between the planes, though it is just 
  one possible interpretation of the vast and unending 
  multiverse. What’s found in the Great Modron Cathedral 
  is also only one half of the whole orrery. The other half 
  is directly below the floor of he dome, accessed only by 
  special allowance by the modron governors, and this half 
  depicts the Material Planes. It is far more vast, owing to 
  the infinite variations of Material Plane worlds, and covers 
  hundreds and hundreds of feet.
  The two halves of the Orrery of the Infinite Planes share 
  a single master cylinder crafted of adamantine, so the 
  movement of one affects the other directly. Those who 
  have witnessed the Material Plane side of the orrery say 
  the models of each world are perfect in every detail and 
  could be used to create maps and uncover lost regions, but 
  the modrons who run it only allow brief visits.
  Palace of Perfect Precept
  The Palace of Perfect Precept is the home of the 
  warforged wizard known as the Mathemagician, who 
  seeks to understand and master the laws of magic by 
  understanding the laws of reality to their finest point. Its 
  palace is bult from marble and designed in an octagon 
  pattern on a vast gear, with eight towers rising up at each 
  angle in the octagon, and a large central keep in the center. 
  The Mathemagician is tended to by numerous golems of 
  variable construction, though its favorite are iron golems, 
  and the enigmatic warforged has not taken any apprentices 
  or passed its knowledge on to date.
  The Mathemagician is largely preoccupied with the 
  study of magical law, which takes its attention away from 
  the general upkeep of the palace, so those duties fall to 
  the golem staff. Majordomo Max, an advanced iron golem, 
  keeps the operation tight and on schedule, and does not 
  allow anything to bother the Mathemagician during the 
  warforged’s many experiments.
  The palace’s layout is a massive focus for magical 
  energy meant to harness and refocus the powers of each 
  arcane magical school, and each tower is devoted to 
  the Mathemagician’s work on a particular school. The 
  libraries are extensive but entirely closed off to outsiders, 
  though the warforged has entertained guests from time 
  to time, normally open-minded archmages from across 
  the multiverse with an interest in pushing the boundaries 
  of arcane knowledge to their absolute limit. Followers of 
  
  Volume XXIII  |  Clockwork Nirvana of Mechanus
  19
  Nomos Prime on Arcadia, whom the Mathemagician refers 
  to as “sheep under an arcane wolf’s eye”, are expressly 
  forbidden from entering the Palace of Perfect Precept.
  Plain of the Gearlost
  Scavenger tribes scrounge and eke out a living amongst 
  the gears of Mechanus, running a low-grade anarchy 
  game on the plane of ultimate law. They are constantly 
  on the move as the modrons and inevitables have orders 
  to remove them on sight, by force if necessary, and the 
  free-spirited tribes never have an interest in going quietly. 
  The tribes, each usually no more than 50 or so humanoids 
  of all types, build temporary fortifications and steal scrap 
  from the Scrap Tracts and junk cogs to use in their own 
  devices. Rogue artificers, junk runners, gear thieves, 
  anarchist priests, and many more fill the ranks of the tribes 
  who make no permanent structures.
  Except for the Plain of the Gearlost. This huge gear, 
  far removed from Regulus, is kept hidden by makeshift 
  scrambler towers that keep its location safe from the 
  constructs of the plane. It is a sacred site to the scavenger 
  tribes who gather on the gear to share stories, rest, and 
  swap news of Mechanus and their quest for anarchy. 
  Statutes constructed of scrap metal stand all around the 
  Plain of the Gearlost, each depicting the leader of a tribe, 
  and when a leader falls the statue is painted with specially 
  prepared black oil paint to mark their end.
  Regulus
  No other place in Mechanus better represents the ideal 
  of Clockwork Nirvana than Regulus, the home of the 
  modrons and their enigmatic god-force, Primus. The realm 
  consists of 64 huge gears, a number that never changes 
  or wavers, each connected and moving in synchronization 
  with the adjacent cogs. Modrons of all shapes and sizes 
  live and work endlessly in Regulus, tending to the duties of 
  managing their ordered society.
  Food is grown and harvested in Regulus for the modrons 
  to eat, though the form the food takes is not natural 
  vegetation. It appears as long-bladed steel grass and 
  grows in perfectly ordered rows on the four food cogs, and 
  nowhere else. Modron houses are blocky simply constructs 
  of metal stacked dozens high, each with just enough room 
  for a single modron to sleep and spend their allotted 15 
  minutes of leisure time each bell cycle (8 hours). Modron 
  soldiers patrol both the borders of Regulus and the interior 
  regions, as there have been incidents of some modrons 
  going rogue and learning to think independently. While this 
  isn’t a crime itself (though modron lawmakers are working 
  to push through legislation to make it illegal, a process 
  that has been held up in the Higher Ethics and Moral 
  Ambiguity Committee for over one thousand years), rogue 
  modrons are asked to leave for free of their independence 
  spreading like a disease, disrupting the ordered structure 
  of Regulus.
  Every modron has a place, and many of those places are 
  in the offices and factories of Regulus. Depending on the 
  caste, the modron may have many duties or few. Those that 
  tend to Primus, their god-entity, are complicated modrons 
  with multifaceted bodies, but even their capability for 
  independent idea is hampered. Which seems to be the way 
  Primus built them, so it’s all according to the grand plan.
  The Tower of Primus and the Great Modron Cathedral 
  sit on the largest and most central gear of Regulus. The 
  Great Modron Cathedral houses the Orrery of the Infinite 
  Planes, a stunning model of the multiverse that attracts 
  visitors from across the planes, while the Tower of Primus 
  is strictly off limits to non-modron personnel. Anyone 
  coming into Regulus on peaceful terms must submit their 
  application to the Department of Border Allowances and 
  Registrations, and if approved the visitor will be issued 
  a guest pass that identifies them as allowed into certain 
  areas of Regulus. Exceptions are flagged and reviewed by 
  the Board of Exceptions to the Border Allowances and 
  Registrations Department, though several subcommittees 
  may have to take up the matter. The entire process is 
  needlessly complicated bureaucracy but the modrons 
  pull it off with cheerful smiles and a never-ending positive 
  attitude towards “The Plan.” Whatever “The Plan” may be.
  Scrap Tract Gamma Eleven
  The Scrap Tracts of Mechanus are where broken gears 
  and other refuse are stored, neat and ordered away 
  from the rest of the plane, until it can be broken down, 
  processed, and recycled into new gears and mechanical 
  parts. There are theoretically an infinite number of 
  Scrap Tracts throughout Mechanus and each has a code 
  designation, such as Scrap Tract Alpha Three and Scrap 
  Tract Omega Thirty. Most house simple scrap pieces from 
  the region they are closest, but a few have specialized 
  purposes. The most famous of these is Scrap Tract 
  Gamma Eleven, a secret repository for anything magical 
  found on Mechanus.
  The modrons responsible for cleanup across the plane 
  occasionally find magical odds and ends, usually left over 
  from travelers who have met an untimely end somewhere 
  on Mechanus. When objects containing inherent magical 
  properties are found, the modrons take the refuse to a 
  sorting facility, and eventually the magical scrap is sorted 
  from the regular scrap and then teleported magically to 
  Scrap Tract Gamma Eleven. This teleportation is unique 
  among the collected junk, as the modrons usually deposit 
  refuse directly into the correct Scrap Tract.
  Rumors abound about the magical treasures found in 
  Scrap Tract Gamma Eleven. The modrons are no help in 
  finding it, as they truly don’t know its location at all, though 
  some inevitables are said to know where it can be found. 
  It has been theorized that the regular reprocessing of 
  junk does not occur in Scrap Tract Gamma Eleven, which 
  means that hidden cylinder contains all of the magical 
  detritus found on Mechanus since the beginning of the 
  multiverse itself. It has become an obsession for a number 
  of Cog Confederates in the Transcendent Academy, some 
  of whom have spent multiple generations trying to locate 
  the elusive site.
  
  Volume XXIII  |  Clockwork Nirvana of Mechanus
  20
  Scriptorium of Law
  The greatest courthouse in all the multiverse and the 
  largest repository of lawful documents is the Scriptorium 
  of Law, which is where the Word of Law passes judgment 
  on criminals and its legion of metal agents carry out the 
  justice of Mechanus. The building is a series of enormous 
  blocks with no windows and only a single set of massive 
  double doors leading to the interior. The exterior is plain 
  gray stone, unadorned and without decoration except 
  for the symbol of infinity (a sideways 8) etched above the 
  doors.
  Inside, the Scriptorium is just as sparse as the exterior, 
  at least for the main levels wherein the courthouse is 
  contained. The Word of Law itself hangs suspended in a 
  fantastically huge chamber in the center of the complex, 
  with adjoining wings holding prisoners awaiting trial 
  and final judgement. Death is the usual verdict for guilty 
  charges of any kind, but there is an appeal process, so 
  canny creatures with knowledge of the law can delay their 
  final sentencing for days, weeks, months, or even years.
  The lower sections of the Scriptorium of Law contain 
  the written laws of Mechanus. Each law decreed by Primus 
  magically appears on a thin sheet of paper-like metal in 
  the Sciptorium’s archives, where they are catalogued by 
  the metal agents and preserved for eternity. No being is 
  allowed into the archives, though representatives of an 
  accused can request laws be brought forth for clarification 
  and evidence. This isn’t necessary for the Word of Law but 
  it understands that lesser beings are not as in tune with 
  every facet of Mechanus law as itself.
  Everything is neat and ordered in the Scriptorium, and 
  scuffles are strictly forbidden by the Word of Law. The 
  metal agents, silver and gold, fulfill the duties of the office, 
  such as bringing in prisoners and carrying out sentences, 
  but the Word of Law itself serves as both prosecutor and 
  judge for any criminal case. Some planar scholars have 
  argued that this is an inherently unfair situation, but 
  the Word of Law is a being completely devoid of bias or 
  personal interest. Or so it would seem, at least.
  Silversprocket
  The most accessible city on Mechanus is Silversprocket, 
  located on an adjacent cog to the Transcendent Academy. 
  It is a well-ordered city of gleaming steel and silver 
  buildings laid out in neat rows, neighborhoods, and 
  districts, with a multitude of residents bustling about 
  their busy lives. Everyone has a job in Silversprocket, 
  from growing and harvesting food to support the city to 
  maintaining law and order, but the vast majority supports 
  the nearby artificers of the Confederacy of the Cog.
  Visitors are required to check in with the Welcome 
  Board, stationed in small buildings around the most 
  commonly used city entrances, but the process is not 
  onerous and most visitors are allowed into Silversprocket 
  with no problems. The city boasts a number of 
  manufacturing plants that can only be found in Mechanus, 
  so they receive deliveries of goods and products from 
  across the multiverse on a regular basis. The artificers 
  of the Transcendent Academy regularly spend leisure 
  time in Silversprocket, and also purchase most of the raw 
  materials and manufactured goods produced by the city. 
  The two share a positive relationship of reciprocity.
  Silversprocket is run by an elected governor who is 
  attended to by the Silversprocket Senate, with individual 
  members elected by the populace. The Silversprocket 
  Senate handles most of the day to day legislation of the 
  city, and they are responsible for the city watch and most 
  of its public service departments. The governor is largely a 
  figurehead with little actual responsibilities, though some 
  have taken a more tyrannical approach to their position 
  than others. The current leader, Governor Kedaja Darlan, 
  is a female dwarf originally from the city of Ravnica. She 
  was elected on a platform of fair operations and good 
  working relationships with Ravnica, the City of Guilds, but 
  some worry that her close ties to the guilds of that city may 
  compromise Silversprocket.
  Transcendent Academy
  The Confederacy of the Cog may be the largest 
  organization of artificers in the multiverse, and they hone 
  their skills and practice their craft at a massive facility in 
  Mechanus known as the Transcendent Academy. Multiple 
  towers rise up above the dense collection of laboratories, 
  workshops, lecture halls, and living quarters that make 
  up the bulk of the academy’s base. The Transcendent 
  Academy rests on a large gear, not as huge as others, and it 
  rotates perpendicular to a larger gear that holds the city of 
  Silversprocket.
  Enterprising artificers from all over submit their 
  applications to join the Transcendent Academy and 
  become a member of the Confederacy of the Cog. Space is 
  limited, but a fair number of students, faculty, and alumni 
  come and go on a regular basis, creating a fluctuating 
  population within the academy grounds. Teachers of all 
  kinds instruct students on the wondrous ways of artificers, 
  touching on subjects such as golem making, armor 
  infusions, alchemy theories, and hundreds of others. 
  Students enrolled in classes at the Transcendent Academy 
  must complete rigorous academic papers and studies in 
  order to keep their place from semester to semester.
  It is all overseen by the Board of Regents that dwell in 
  the largest tower in the academy grounds. Membership in 
  the board is by board approval only, and by ancient bylaws 
  the number must be a prime number. It’s been as low as 7 
  in the past, but the Board of Regents currently sits at 17 
  today. Each voice on the board is as equal as another, as 
  no president or ruling force sits above them, but they do 
  have to answer to suppliers and a host of underwriters that 
  work with the academy across the multiverse.
  Fantastic works of engineering are produced every 
  day by the students and faculty at the academy, and 
  the place has a well-earned reputation for producing 
  competent and worldly members. Students that attend 
  the Transcendent Academy are not automatically inducted 
  into the Confederacy of the Cog, and in fact many students 
  leave without having any interest in joining the artificer 
  organization. For the Cog Confederates, however, the 
  Transcendent Academy functions as their de facto base 
  and the home to their greatest experiments.
  
  Volume XXIII  |  Clockwork Nirvana of Mechanus
  21
  Adventure Hooks
  Adventure and excitement can be found amongst the gears 
  of Mechanus as surely as any other plane. On the surface, 
  the rigid structure and extreme lawful bent of the plane 
  and its inhabitants may seem to deter the chaotic forces 
  that draw adventurers, but Mechanus is a huge place 
  (infinite even!), and strange things happen all the time.
  Tier 1 (levels 1-4)
  … A modron approaches the party in whatever city they 
  happen to be in at the time. The modron has become 
  separated from Mechanus and needs assistance in going 
  home. It has no idea how it arrived in the city, and when 
  the characters follow the clues they discover a cabal of 
  cultists that accidentally called the creature away from the 
  Clockwork Nirvana. Can the characters recreate the gate? 
  What are the true goals of the cultists?
  … A group of clockwork golems have gone insane and 
  are terrorizing a local neighborhood! All of the clockwork 
  golems share a distinct design that marks them as from 
  the same owner, but there’s no sign of who or what 
  the owner is. Investigation leads the characters to the 
  Confederacy of the Cog and the Transcendent Academy, 
  where it is discovered a saboteur was using the clockwork 
  golems to steal items, but they went out of control due to 
  lax construction standards.
  … Formians from a hive-city in Mechanus have breached 
  the planar paths and established a colony near the 
  characters’ home town. The insectoid creatures begin to 
  meet with the locals and offer them an ultimatum – submit 
  to the formians or be subjugated by force. The characters 
  are asked to reason with the queen, who is on a gear in 
  Mechanus. Unfortunately, this formian queen is more 
  interested in expansion at all costs to the party must find 
  an alternate place for her to expand her colony. A nearby 
  gear offers an option but it needs to be cleared of the local 
  inhabitants, buzzflies primarily.
  Tier 2 (levels 5-10)
  … The characters disrupt a ritual by Asmodeus cultists, 
  only to learn that it was tied to large machinations linked 
  to the Crimson Clock on Mechanus. The characters must 
  go to the clock and put an end to the ambitious high 
  priestess who believes she has the secret knowledge of 
  what the Crimson Clock is counting down to – Asmodeus’ 
  arrival in Mechanus itself! She is attended by devils but 
  hasn’t broken any laws, so the party must stop her and her 
  allies.
  … A march of modrons suddenly appears and moves 
  through the area nearby the party. It isn’t the full Great 
  Modron March, only a lesser march, but the single-minded 
  modrons trample through the streets, heedless of the 
  disruption they are causing. They need help to finish their 
  march as the creatures along the way are more than a 
  match for the less-combat skilled constructs.
  Tiers 3 and 4 (levels 11+)
  … The machinations of the Glass God are beginning to 
  encroach on the fabric of Mechanus. The characters are 
  invited to the Palace of Perfect Precept, the home of the 
  Mathemagician, who proposes a strike mission to weaken 
  the Glass God. The characters must go into the Glass 
  Spires and inscribe a phrase of power using a specially 
  prepared powder on the interior of one of the structures. 
  Glass hounds and glassy-eyed servants stand in their way, 
  but in the end is the Mathemagician’s calculations correct? 
  The Glass God originates from the Far Realm entirely 
  different cosmic laws.
  … A marut inevitable has confronted an ally of the party, 
  claiming they broke a contract signed in the Hall of 
  Concordance. It is a mistake but the marut is convinced 
  it’s real, so the ally is brought to the Scriptorium of Law 
  to await judgement by the Word of Law. The characters 
  are asked to seek out who is behind the duplicity while 
  the Word of Law is stilled. Can the party find the real 
  culprit in time? The trip may take them to anywhere in the 
  multiverse but ultimately ends up back in Mechanus to 
  argue for their ally’s freedom.
  
  Volume XXIII  |  Clockwork Nirvana of Mechanus
  22
  Random Encounter Tables
  The below tables can be used by the Dungeon Master 
  as a source of inspiration when a party of characters are 
  traveling through the Clockwork Nirvana of Mechanus. 
  Two tables are provided, one for the Great Gears and 
  another for the Scrap Tracts. Look at each one as a 
  springboard for new adventure ideas, or as a means of 
  highlighting the nature of the plane for the players.
  Great Gears
  1d100
  great gearS enCounter
  01-05
  A few buzzflies looking for an easy meal
  06-10
  Scavengers (bandits) on the run from an 
  inevitable patrol
  11-15
  A gearwraith hunting for life
  16-20
  A colony of myconids living peacefully on a 
  gear
  21-25
  Four duodrones repairing the teeth of a 
  broken cog
  26-30
  A lawmage from Ravnica inspecting a site
  31-35
  Three silver metal agents hunting down a 
  fugitive
  36-40
  A artificer from the Transcendent Academy 
  studying a puzzling gear
  41-45
  An oil jelly slithering through the gears
  46-50
  A gynosphinx puzzling over the nature of 
  the multiverse
  51-55
  Formian soldiers watching over the area
  56-60
  A hadrut inevitable guarding an invisible 
  border
  61-65
  Clockwork golems on an errand from their 
  master
  66-70
  A clay golem searching for its creator
  71-75
  An artificer and a herd of iron defenders 
  looking for rare gears
  76-80
  A squad of quadrones preparing for combat
  81-85
  Two stone golems standing guard over a 
  secret door
  86-90
  A glass hound jumping between angles
  91-95
  A fugitive from the Word of Law
  96-00
  An inactive marut waiting to be summoned
  Scrap Tract
  1d100
  SCrap traCt enCounter
  01-10
  Oil jellies looking for a meal
  11-20
  Scavengers picking through the rubble
  21-30
  Silver metal agents looking for lawbreakers
  31-40
  A colony of unassuming myconid
  41-50
  Devil cultists looking for lost pieces
  51-60
  A rogue modron trying to find a purpose
  61-80
  Worthless junk scrap
  81-90
  Valuable scrap that is too large to move 
  easily
  91-00
  Valuable transportable scrap
  
SOURCE: textdata/thevault/Dungeons & Dragons [multi]/5th Edition (5e)/3rd Party/Dave Coulson/Codex of the Infinite Planes - Vol 23 - Mechanus.pdf