TEXT:  
   
   
   
   
   
   
   
   
   
   
   
   
   
  by Ruslan Kim 
   
   
   
   
   
  DUNGEONS & DRAGONS, D&D, Wizards of the Coast, Forgotten Realms, Ravenloft, Eberron, the dragon ampersand, Ravnica and all other Wizards 
  of the Coast product names, and their respective logos are trademarks of Wizards of the Coast in the USA and other countries. This work contains 
  material that is copyright Wizards of the Coast and/or other authors. Such material is used with permission under the Community Content Agreement 
  for Dungeon Masters Guild. All other original material in this work is copyright 2019 by Ruslan Kim and published under the Community Content 
  Agreement for Dungeon Masters Guild. 
  
   
  About this Guide 
  Combat is one of three main pillars of the game, 
  apart from exploration and interaction. And it 
  takes a lot of time to prepare and run good 
  combat encounter. The goal of this guide is to 
  help DMs who are running Waterdeep: Dungeon 
  of the Mad Mage adventure to get better 
  understanding on how to run combat encounters, 
  how to make them coherent, memorable and fun! 
   
  Preparation process divided into 3 steps: 
  1. Determining Encounter Difficulty. 
  2. Determining Surprise. 
  3. Determining Creatures’ Tactics. 
   
  First step will give you general understanding 
  about how difficult combat encounter might be 
  for your player characters. Each level of WDMM is 
  designed for PCs of particular level. I use a 
  guideline from Encounter Building section in 
  Xanathar’s Guide to Everything (XGE, p. 88) to 
  evaluate how many PCs of corresponding level 
  should be in the party to overcome the encounter. 
  Math is simple. If you have the same number of 
  PCs – it is good fight. If you have more PCs (2/3 of 
  number of PCs is needed) – they will pass it with 
  ease, but it still be challenging. If you have less 
  PCs (3/2 of number of PCs is needed) – encounter 
  will be hard, but still winnable. Also, I put notes 
  about combat difficulty, which I think is 
  important. Depending on this information you 
  can adjust the encounter for your group, skip it 
  entirely or think about possible defeat 
  consequences. 
   
  Second step is always up to DM, so you should be 
  prepared in advance. General guidance is written 
  in Player’s Handbook (PHB, p. 189). Basically, you 
  should determine who is surprised when the first 
  round of combat begins. To do so, you should 
  know answers for these questions: 
  Are creatures trying to hide? They roll Stealth. 
  Are they successful? Compare results to PC’s 
  Passive Perception score. 
  Are PCs trying to hide? They roll Stealth.  
  Are they successful? Compare results to 
  creatures’ Passive Perception score. 
  Based on the results you will understand who 
  will take actions in the first round of combat and 
  who will not. I also put my notes for the 
  encounters when circumstances may differ from 
  the standard procedure. 
   
  Third step will help you to understand how to use 
  creatures in combat. Where should they stand? 
  What course of action will be most efficient and 
  logical depending on the lore? Who do they need 
  to attack? Will they fight to the death? Will they 
  flee or surrender? I also put more detailed 
  explanation on how some creature’s abilities and 
  traits work. 
   
  Abbreviations and Font Styles 
  The following abbreviations are used throughout this 
  guide: 
  PHB = Player’s Handbook 
  MM = Monster Manual 
  DMG = Dungeon Master’s Guide 
  SCAG = Sword Coast Adventurer’s Guide 
  XGE = Xanathar’s Guide to Everything 
  VGTM = Volo’s Guide to Monsters 
  MTOF = Mordenkainen’s Tome of Foes 
  WDMM = Waterdeep: Dungeon of the Mad Mage 
  WDH = Waterdeep: Dragon Heist 
  PC(s) = Player Character(s) 
  AC = Armor Class 
  DC = Difficulty Class 
  CR = Challenge Rating 
  hp = hit points 
  gp = gold piece(s) 
  AoE = Area of Effect 
  RAW = Rules as Written 
   
  The following font styles are used throughout this 
  guide: 
  Bold style is used for the creatures’ names 
  Italic style is used for the Spells. 
  Bold Italic style is used for the Abilities and Traits. 
  
   
  Level 19: Caverns of Ooze 
  This level is designed for four 15th level PCs. If 
  you have more than 4 PCs, you can add more 
  creatures or maximize their hp to make combat 
  encounters more challenging. If you have less 
  PCs, you can decrease the number of creatures in 
  combat or use less optimal tactics. All creatures 
  in Encounter Difficulty section are compared to 
  15th level PCs. 
   
  Area 1c 
  Encounter Difficulty 
  1 Marid (CR 11, MM, p. 141) = 3 PCs 
  1 Swarms of Quippers (CR 1, MM, p. 338) = 1 PC 
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. 
   
  Creatures’ Tactics 
  Marids are proud genies native to Elemental 
  Plane of Water (PHB, p. 300). They can negotiate, 
  flee, surrender and take captives. 
   
  The Marid can fly and also has swim speed so 
  make it stay out of melee reach or under the 
  water between its turns. Fighting underwater 
  without swim speed or appropriate weapons is 
  harder for PCs (See PHB, p. 198) and water also 
  gives Resistance to fire damage. At the first round 
  of the combat make the Marid cast Fog Cloud 
  around itself. It has Blindsight and good 
  Constitution saves, so making PCs inside spell’s 
  AoE effectively Blinded (PHB, p. 290) is good 
  defensive tactics. On the next turns make the 
  Marid use Water Jet if it can target at least 2 PCs, 
  otherwise make it use Multiattack against less 
  armored PC. 
   
  Quippers are beasts, so they can’t surrender, take 
  captives or communicate without Speak with 
  Animals spell or similar abilities, but they can flee. 
   
  Make the Swarm of Quippers use Bite against 
  nearest PC. 
  Area 2 
  Encounter Difficulty 
  12 Orogs (CR 2, MM, p. 244) = 3 PCs 
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. 
   
  Creatures’ Tactics 
  Orogs are orcs blessed with a surprisingly keen 
  intellect that ordinary orcs believe is a gift from 
  the orc goddess Luthic. They can negotiate, flee, 
  surrender or take captives. 
   
  Make the Orogs use Multiattack against less 
  armored or Stunned PC. The Orog can use 
  Aggressive trait as Bonus Action to reach its 
  target when needed. Make the Orog use Javelin 
  only if there is no chance to attack in melee. 
   
  Area 5a 
  Encounter Difficulty 
  3 Intelligent Black Puddings (CR 4, MM, p. 240, 
  with changes) = 2 PCs 
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. 
   
  Creatures’ Tactics 
  These creatures are followers of Ghaunadaur, 
  formless mad god of ooze, member of Dark 
  Seldarine pantheon (MTOF, p. 53), transformed 
  into oozes by Halaster. They understand 
  languages, which means they can communicate 
  with creatures that have Telepathy. They won’t 
  flee, surrender or take captives. 
   
  Make the Intelligent Black Pudding cast 
  Darkness on itself, so PCs will have Disadvantage 
  on attacks against it and the Intelligent Black 
  Pudding will have Advantage against PCs inside 
  spell’s AoE because it has Blindsight. Make it also 
  
   
  cast Shield as Reaction to avoid some hits during 
  PCs’ turns. On the next turn make the Intelligent 
  Black Pudding cast Melf’s Acid Arrow against less 
  armored PC. After that make the Intelligent 
  Black Pudding use Pseudopod against less 
  armored PC within reach. Successful Pseudopod 
  attack makes any non-magical armor less 
  effective. After PC makes successful attack with 
  slashing weapon or with the spell dealing 
  lightning damage, the Pudding won’t lose hp. 
  Instead, it can use its Reaction to Split. If it does 
  so, two new Medium Puddings appears and since 
  they are new combatants, they also have 
  Reactions available and also can use Split. Small 
  Black Puddings are not able to use Split ability, 
  but they are still immune to slashing and 
  lightning damage. 
   
  Area 7 
  Encounter Difficulty 
  2 Nalfeshnees (CR 13, MM, p. 50) = 10 PCs 
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. 
   
  Creatures’ Tactics 
  Demons are the embodiment of chaos and evil 
  existing only to destroy. They can’t truly die on 
  the Material Plane, so they don’t surrender or 
  flee. They can communicate via Telepathy or in 
  Abyssal language. They don’t take captives and 
  show no mercy to fallen enemies. 
   
  The Nalfeshnee can fly so make it use hit and run 
  tactics and stay in the air out of melee reach 
  between its turns. Demons have very good 
  protection from magic thanks to resistance from 
  cold, fire and lightning and Advantage on saves 
  from Magic Resistance trait, so make the 
  Nalfeshnee use Multiattack against PC with 
  strong ranged attacks who isn’t Frightened (PHB, 
  p. 290) by Horror Nimbus.  
   
  Area 9 
  Encounter Difficulty 
  5 Gargoyles (CR 2, MM, p. 140) = 1 PC 
   
  Surprise 
  The Gargoyles can surprise PCs automatically 
  thanks to False Appearance trait. 
   
  Creatures’ Tactics 
  Gargoyles are cruel elemental creatures. They are 
  following simple orders given them by their 
  master. They can negotiate in Terran 
  (Primordial), flee, surrender or take captives 
  depending on the orders given. 
   
  The Gargoyles can fly so make them use hit and 
  run tactics and stay in the air out of melee reach 
  between their turns. Make them focus on less 
  armored PC with their Multiattack. 
   
  Area 11a 
  Encounter Difficulty 
  6 Galeb Duhr (CR 6, MM, p. 139) = 6 PCs 
  Note. Fight in this area might alert creatures 
  from Area 11b. 
   
  Surprise 
  The Galeb Duhr can surprise PCs automatically 
  thanks to False Appearance. Their Tremorsense 
  automatically detects non-flying PCs. 
   
  Creatures’ Tactics 
  Galeb duhr are among the most intelligent 
  elemental creatures. They can negotiate, flee, 
  surrender or take captives. 
   
  Make the Galeb Duhr use Animate Boulders in 
  the first round of combat. As a DM you can roll 
  separate Initiative for new combatants or make 
  them take their turns right after the Galed Duhr. 
  On the next turn make all Galeb Duhr use 
  Rolling Charge and Slam focusing on less 
  armored or Prone PCs. 
  
   
  Area 11b 
  Encounter Difficulty 
  1 Dao (CR 11, MM, p. 141) = 3 PCs 
  2 Medusas (CR 6, MM, p. 214) = 2 PCs 
  Note. Fight in this area might alert creatures 
  from Area 11a. 
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. 
   
  Creatures’ Tactics 
  Dao are greedy, malicious genies from the 
  Elemental Plane of Earth (PHB, p. 300). They can 
  negotiate, flee, surrender or take captives. 
   
  The Dao has Earth Glide trait so make it hide 
  underground between its turns so PCs will be 
  forced to use Ready action. Make the Dao cast 
  Phantasmal Killer targeting martial PC at the first 
  round of the combat. On the next turns make the 
  Dao use Multiattack targeting less armored PC. 
  Always use Maul instead of Fist. 
   
  A victim of a terrible curse, the serpent-haired 
  medusa petrifies all those who gaze upon it, 
  turning creatures into stone monuments to its 
  corruption. Medusas are smart enough to 
  negotiate, flee, surrender or take captives. 
   
  Petrifying Gaze works this way. Each PC starting 
  turn within 30 ft. of the Medusa must avert his or 
  her eyes, which effectively inflicts Blinded 
  condition (PHB, p. 290), or make DC 14 
  Constitution saving throw. Surprised PCs can’t 
  avert their eyes. If PC’s save total is 9 or less, he 
  or she becomes Petrified. If PC’s save total is 
  between 10 and 13, he or she becomes 
  Restrained and must roll save again at the end of 
  next turn. Make the Medusa use Multiattack 
  against less-armored or Blinded PC. Use 
  Longbow only if there is no chance to attack in 
  melee. 
   
   
   
  Area 12 
  Encounter Difficulty 
  3 Intelligent Black Puddings (CR 4, MM, p. 240, 
  with changes) = 2 PCs 
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. 
   
  Creatures’ Tactics 
  See Area 5a. 
   
  Area 13a 
  Encounter Difficulty 
  4 Gray Slaadi (CR 9, MM, p. 274) = 8 PCs 
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. 
   
  Creatures’ Tactics 
  Slaadi are the creatures of pure chaos native to 
  Outer Plane, called Ever-Changing Chaos of 
  Limbo (PHB, p. 300). According to MM, their goal 
  is to sow discord on the Material Plane. Gray 
  slaadi are intelligent enough to negotiate, flee, 
  surrender or take captives. 
   
  Fear spell is a good AoE disable, so make the 
  Gray Slaad cast it targeting as many PCs as 
  possible. The less PCs will be able to attack the 
  Gray Slaadi the better. After that, make it use 
  Multiattack against less armored PC. Always use 
  Greatsword instead of Claw. Use Fireball, if you 
  can target 3 and more PCs. Use Invisibility or Fly 
  spells, if you decide that it is time to flee. At the 
  beginning of each turn the Gray Slaad regains 10 
  hp, if nothing like Chill Touch cantrip prevents its 
  Regeneration trait from function. 
   
   
  
   
  Area 13g 
  Encounter Difficulty 
  1 Mind Flayer Arcanist (CR 8, MM, p. 221, with 
  changes) = 2 PCs 
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. 
   
  Creatures’ Tactics 
  Mind flayers are psionic tyrants and slavers who 
  devour brains of intelligent creatures. They can 
  negotiate, flee, surrender or take captives. 
   
  The Mind Flayer Arcanist can use Lair action to 
  create duplicate with statistics of normal Mind 
  Flayer before beginning of the combat. You can 
  also make the Mind Flayer Arcanist cast Wall of 
  Force around itself before the combat in order to 
  prevent alpha strike from the party. Mind Flayer 
  Arcanist can stay inside Wall of Force sphere 
  using Dodge action, making duplicate Mind 
  Flayer fight outside and recreate it using Lair 
  action on Initiative count 20 if needed. Some PCs’ 
  spells might be cast or created inside Wall of 
  Force to break Mind Flayer Arcanist’s 
  Concentration or PCs can destroy it casting 
  Disintegrate, so using this tactic is far from being 
  invulnerable. Once the Mind Flayer Arcanist 
  expends all 5th level slots on Wall of Force it must 
  use different tactics. Mind Blast is the most 
  powerful ability the Mind Flayer Arcanist and 
  its duplicates have, because it deals damage and 
  disables PCs within good AoE, so make them use 
  it every time it’s available. The Mind Flayer 
  Arcanist can use its Reaction to cast Shield for 
  additional protection. If Mind Blast is not 
  available, make the Mind Flayers cast Dominate 
  Monster, but don’t forget that this will break 
  Concentration on Wall of Force if it’s still active. 
  The Mind Flayers are smart enough to use this 
  spell against martial PCs, rather than spellcasters. 
  Next time Mind Blast is not available make the 
  Mind Flayer Arcanist cast Lightning Bolt 
  targeting as many PCs as possible. Don’t forget 
  that Stunned PCs automatically fail Dexterity 
  saves. The duplicate can attack in melee focusing 
  on less armored Stunned PC. Tentacles and 
  Extract Brain attacks work in conjunction. 
  Successful Tentacles attack inflicts Grappled 
  condition automatically and if PC fails saving 
  throw it also inflicts Stunned condition. Stunned 
  condition includes Incapacitated condition which 
  allows the Mind Flayer use Extract Brain next 
  round. According to WDMM, the Mind Flayer 
  Arcanist surrenders if reduced to 55 hp. 
   
  Area 14 
  Encounter Difficulty 
  1 Huge Gray Ooze (CR 8, MM, p. 240, with 
  changes) = 2 PCs 
   
  Surprise 
  The Gray Ooze can surprise PCs automatically 
  thanks to False Appearance trait. 
   
  Creatures’ Tactics 
  See Area 5a for general description of this 
  creature. 
   
  Make the Huge Gray Ooze use Enlarge and 
  Invisibility before the start of the combat and 
  stay motionless until PC approaches to melee 
  reach. False Appearance makes the Ooze 
  unnoticeable by general means, so it can easily 
  surprise the party. Make the Ooze use 
  Pseudopod against less armored PC within reach. 
  Don’t forget, that Pseudopod damages non-
  magical armor and Corrode Metal damages non-
  magical weapons made of metal. 
  
SOURCE: textdata/thevault/Dungeons & Dragons [multi]/MGtCE of DotMM 1-23/Monsters' Guide to Combat Encounters - For Dungeon of the Mad Mage Level 19 - Caverns of Ooze.pdf