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 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 could 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 creature’s names 
  Italic style is used for the Spells. 
  Bold Italic style is used for the Abilities and Traits. 
  
   
  Level 9: Dweomercore 
  This level is designed for four 10th level PCs. If 
  you have more than 4 PCs, you can add more 
  creatures to make combat encounters more 
  challenging. If you have less PCs, then you can 
  decrease the number of creatures in combat or 
  use less optimal tactics. All creatures in 
  Encounter Difficulty section are compared to 10th 
  level PCs. 
   
  Area 1a 
  Encounter Difficulty 
  1 Left hand of Manshoon (CR 12, MM, p. 342, 
  with changes) = 4 PCs 
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. 
   
  Creatures’ Tactics 
  Left hand of Manshoon is undead guardian. It 
  won’t communicate, surrender or take captives, 
  but it can flee if you decide so. 
   
  Left hand of Manshoon is Archmage. It’s very 
  vulnerable to physical attacks and it’s not very 
  strong opponent for 10th level party. This 
  particular Archmage can fly so make it stay in 
  the air away of melee reach. Assume that Mage 
  Armor and Mind Blank were pre-casted. Start the 
  fight with Time Stop. It will give the Archmage an 
  opportunity to take minimum 2 turns without 
  interruption. During the first turn make it cast 
  Mirror Image. Next turn, make it cast Wall of 
  Force trapping inside the dome one or two 
  martial PCs. If it has one more turn, use it to cast 
  6th level Cone of Cold, which will end Time Stop. If 
  it has more free turns you can make it cast Fire 
  Shield before Cone of Cold. The Archmage has 
  resistance to damage from spells already, but 
  additional damage to melee attackers might be 
  helpful. Continue casting Cone of Cold or 4th level 
  Lightning Bolt spells targeting as many PCs as 
  possible. Use Counterspell against harmful spells. 
  If you decide that it’s time to flee, cast Teleport. 
  Area 4 
  Encounter Difficulty 
  2 Mezzoloths (CR 5, MM, p. 313) = 4 PCs 
  Note. These creatures are not going to attack 
  the party without reason. 
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. 
   
  Creatures’ Tactics 
  Mezzoloth, as any yugoloth (kind of mercenary 
  fiends), can’t be killed anywhere outside 
  Gehenna, their home plane. They won’t flee, 
  surrender or take captives but can negotiate 
  using Telepathy. 
   
  The Mezzoloth has Blindsight and Poison 
  Immunity which allows it to fight inside Cloudkill 
  AoE without consequences. Use this spell in the 
  first round of combat and make the Mezzoloths 
  use Multiattack against blinded less-armored 
  PCs. Since it is heavily obscured area the 
  Mezzoloth gains benefits of Invisible condition 
  (PHB, p. 291).  If Concentration on Cloudkill is 
  broken, second Mezzoloth can cast it once again. 
  Dispel Magic can be useful to end spells cast by 
  PCs. 
   
  Area 6 
  Encounter Difficulty 
  1 Archmage (CR 12, MM, p. 342) = 8 PCs 
  1 Oni (CR 7, MM, p. 239) = 3 PCs 
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. 
   
  Creatures’ Tactics 
  Archmage is intelligent enough to negotiate, flee, 
  surrender or take captives. See Area 1a for his 
  tactics. 
   
  
   
  Oni, also known as ogre mages, are cunning and 
  cruel creatures. They can negotiate, flee, 
  surrender or take captives. They covet magic 
  items, so you can make them focus on PCs who 
  have it. 
   
  Make the Oni cast Cone of Cold targeting as many 
  PCs as possible. Fly speed and Glaive attack with 
  10 ft. Reach allows the Oni to stay in the air out of 
  melee reach and hit-and-run without getting 
  opportunity attacks, but don’t forget that it must 
  protect the Archmage. Make the Oni cast 
  Invisibility and fly away if you decide that it’s time 
  to flee. Alternatively, you can make the Oni flee 
  through pneumatic tubes under effect of Gaseous 
  Form spell. 
   
  Area 7 
  Encounter Difficulty 
  1 Mind Flayer Arcanist (CR 8, MM, p. 222) = 4 
  PCs 
  Note. This creature is not going to attack the 
  party without reason. 
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. 
   
  Creatures’ Tactics 
  Mind flayers are psionic tyrants and slavers who 
  devour brains of intelligent creatures. They are 
  very smart and can negotiate, flee, surrender or 
  take captives.   
   
  At the beginning of the combat make Mind 
  Flayer Arcanist use Mind Blast targeting as 
  many PCs as possible. It is recommended to use 
  Mind Blast every time it recharges because it 
  deals damage and disables PCs at the same time 
  and doesn’t require Concentration. During PCs’ 
  turns make it use its Reaction to cast Shield or 
  Counterspell. On the next rounds make it cast 4th 
  or 5th level Lightning Bolt spells targeting as many 
  PCs as possible. Don’t forget that Stunned PCs 
  (PHB, p. 291) automatically fails Dexterity saving 
  throws. Using Mind Blast, Lightning Bolt and 
  Shield spells should be enough to challenge the 
  party, but you can also make the Mind Flayer 
  Arcanist use other options. Dominate Monster is 
  very powerful 8th level spell, but it doesn’t do 
  anything if PC succeeds on save. If you decide to 
  use it, assume that the Mind Flayer Arcanist is 
  smart enough to target martial PCs, rather than 
  spellcasters, because spellcasters usually have 
  higher bonus to Wisdom saves. Tentacles and 
  Extract Brain attacks work in conjunction. 
  Successful Tentacles attack inflicts Grappled 
  condition (PHB, p. 290) automatically and if PC 
  fails saving throw it also inflicts Stunned 
  condition (PHB, p. 291). Stunned condition 
  includes Incapacitated condition (PHB, p. 291) 
  which allows Mind Flayer Arcanist to use 
  Extract Brain next turn. Note that if PC dies 
  because of Extract Brain ability neither Revivify 
  nor Raise Dead spells won’t work, because they 
  don’t restore any missing body parts. The easiest 
  way to bring PC back to life is Resurrection spell 
  which is available for bards and clerics at level 13 
  earliest. If you decide that it’s time to flee, make 
  the Mind Flayer Arcanist cast Invisibility and run 
  away. You can also make it cast Wall of Force to 
  block the path for the pursuers. If there is no 
  chance to run, you can make the Mind Flayer 
  Arcanist cast Wall of Force around itself and start 
  negotiations. 
   
  Area 11f 
  Encounter Difficulty 
  1 Ogre Zombie (CR 2, MM, p. 315) = 1 PC 
  Note. This is easy encounter, so you can skip it. 
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. 
   
  Creatures’ Tactics 
  Zombies are mindless servants. They won’t 
  communicate, flee, surrender or take captives.  
   
  Make the Ogre Zombie use Morningstar against 
  nearest PC. Roll a die, if several PCs are within 
  same reach, to determine random target. 
   
  
   
  Area 13a 
  Encounter Difficulty 
  1 Drow Mage (CR 7, MM, p. 129) = 3 PCs 
  Note. This creature is not going to attack the 
  party without reason. 
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. 
   
  Creatures’ Tactics 
  According to MM and MTOF, drow are selfish, 
  cruel and treacherous creatures, who believe in 
  their supremacy to all other. They especially hate 
  surface elves, so you can focus on elf or half-elf 
  PCs in combat. Drow are intelligent enough to 
  negotiate, flee, surrender or take captives. 
   
  Make Drow Mage to cast Greater Invisibility at 
  the beginning of the fight. Next round make it try 
  summoning Shadow Demon. You can also make 
  the Drow Mage cast Misty Step before or after 
  using Summon Demon. On the next rounds cast 
  5th level Lightning Bolts targeting as many PCs as 
  possible. Don’t forget to cast Shield and assume 
  that Mage Armor was pre-casted before the 
  encounter. If you decide that it’s time to flee make 
  the Drow Mage cast Fly or Greater Invisibility and 
  run away. You can make it cast Misty Step to move 
  a bit faster. 
   
  Area 13b 
  Encounter Difficulty 
  1 Nycaloth (CR 9, MM, p. 311) = 5 PCs 
  Note. This creature is not going to attack the 
  party without reason. 
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. 
   
  Creatures’ Tactics 
  Nycaloths are yugoloth – neutral evil mercenary 
  fiends from Outer plane called Gehenna (PHB, p. 
  300). They won’t flee, surrender or take captives 
  but can communicate using Telepathy. 
   
  Make the Nycaloth cast Mirror Image at the start 
  of the combat, it is a very good defensive spell 
  which doesn’t require Concentration. After that, 
  make the Nycaloth use Multiattack against less 
  armored PC. The Nycaloth can fly, so make it use 
  hit and run tactics, staying in the air out of melee 
  reach between its turns. Always use Greataxe 
  instead of Claw because the latter requires a lot 
  of rolls which will slow down the pace of combat 
  and deals less damage until fourth hit. It is also 
  easily countered with magical healing. Use 
  Teleport as part of Multiattack to reach and 
  attack fleeing PCs. 
   
  Area 14 
  Encounter Difficulty 
  1 Mage (CR 6, MM, p. 347) = 2 PCs 
  Note. This creature is not going to attack the 
  party without reason. 
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. 
   
  Creatures’ Tactics 
  Mage is intelligent enough to negotiate, flee, 
  surrender or take captives. 
   
  Start the fight with Greater Invisibility. It will 
  protect the Mage from lot of spells that require 
  seeing (especially, Counterspell) and give 
  Disadvantage to attacks against her. Cone of Cold 
  is the most damaging spell the Mage has. You can 
  also make her cast 5th level Fireball if you can 
  target more PCs within its AoE. Assume that 
  Mage Armor was pre-casted before the encounter. 
  Use the Mage’s reaction to cast Shield against 
  attacks or Counterspell against harmful spells. 
  Note that you can use Counterspell on Mage’s 
  own turn against PC’s Counterspell. If you decide 
  that it’s time to flee make the Mage cast Fly, 
  Invisibility or Greater Invisibility and run away. 
  You can also make it cast Misty Step to move a bit 
  faster. 
  
   
  Area 15a 
  Encounter Difficulty 
  1 Arcanaloth (CR 12, MM, p. 311) = 4 PCs 
  Note. This creature is not going to attack the 
  party without reason. 
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. 
   
  Creatures’ Tactics 
  Arcanaloths are yugoloth – neutral evil fiends 
  from Outer plane called Gehenna (PHB, p. 300) 
  who often serve as mercenaries. Arcanaloth is 
  very intelligent, so it can flee, surrender or take 
  captives. It can communicate in all languages or 
  using Telepathy. 
   
  This area is protected by Antipathy spell, so PCs 
  must make DC 17 Wisdom save or become 
  Frightened (PHB, p. 290) and spend all 
  movement to leave spell’s AoE. Successful save 
  grants immunity to this effect for 1 minute. 
  Actually, 60 ft. radius of the spell should also 
  include Area 14, but it isn’t mentioned anywhere 
  in the book. As a DM you can rule that it only 
  works inside Area 15a. The Arcanaloth has 
  decent AC and hp and it can cast Shield or 
  Counterspell as a Reaction to improve its defenses 
  even further. If it has some time before combat, 
  for example before it cast Dimension Door to 
  reach Area 1a, you can make it cast Mirror Image. 
  The Arcanaloth is immune to Charmed condition 
  (PHB, p. 290) so it doesn’t need to pre-cast Mind 
  Blank that much. It’s better to save this spell slot 
  for something else. Fear is a good AoE disable, so 
  make the Arcanaloth use this spell targeting as 
  many PCs as possible at the beginning of the fight. 
  As an alternative, you can make it cast 8th level 
  Hold Monster targeting 4 PCs. Note, that the 
  Arcanaloth is under effect of Alter Self and once 
  it casts other Concentration spell its disguise 
  ends. On the next rounds make the Arcanaloth 
  cast 6th and 7th level Chain Lightning targeting as 
  many PCs as possible. Note, that Paralyzed PCs 
  fail Dexterity saves automatically. If you decide 
  that it’s time to flee make it cast Dimension Door. 
  Area 16 
  Encounter Difficulty 
  1 Mage (CR 6, MM, p. 347) = 2 PCs 
  2 Will-o’-wisps (CR 2, MM, p. 301) = 1 PC 
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. 
   
  Creatures’ Tactics 
  Mage is intelligent enough to negotiate, flee, 
  surrender or take captives. See Area 14 for his 
  tactics. 
   
  Will-o’-wisps are the souls of evil creatures. They 
  feed on despair and fear. According to MM, they 
  rarely speak, and they are intelligent enough to 
  flee. They won’t take captives or surrender. 
   
  Make the Will-o’-wisps use Shock as an Action, 
  and if PC is down, use Consume Life as a Bonus 
  Action. You can make Will-o’-wisps use 
  Incorporeal Movement to hide from PCs’ attacks 
  under the floor between their turns. 
   
  Area 17 
  Encounter Difficulty 
  3 Archmages (CR 12, MM, p. 342, with changes) 
  = 24 PCs 
  Note. This encounter is designed to test one 
  spellcaster PC and it is very hard even for the full 
  party. I’d suggest to roll separate Initiative for 
  each statue and have no spells pre-casted. 
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. 
   
  Creatures’ Tactics 
  See Area 1a. Make the Archmages use Time Stop 
  to cast Mage Armor, Mirror Image, Fire Shield and 
  if there is a chance Cone of Cold. If Time Stop gave 
  to Archmage 5 free turns you can make it cast 
  Wall of Force on 4th turn to trap one martial PC. 
  
   
  Area 20 
  Encounter Difficulty 
  1 Slaad Tadpole (CR 1/8, MM, p. 274) = 1 PC 
  or 
  1 Blue Slaad (CR 7, MM, p. 274) = 3 PCs 
  Note. As a DM you can decide whether there 
  will be Slaad Tadpole, or it grows to Blue Slaad. 
   
  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. Slaad 
  tadpole is mindless so it won’t communicate, flee, 
  surrender or take captives. Blue slaadi can 
  communicate using Telepathy but it is up to DM 
  if it will flee, surrender or take captives. 
   
  The Slaad Tadpole has only one attack option, so 
  make it use Bite against nearest PC. 
   
  The Blue Slaad must spread chaos phage in 
  order to bring to the world more slaadi. Make it 
  use Multiattack against less-armored PC. Once 
  PC fails save against the disease from Claw attack 
  make the Blue Slaad attack next PC. 
   
  Area 22 
  Encounter Difficulty 
  2 Poison Weirds (CR 4, MM, p. 299, with 
  changes) = 2 PCs 
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. 
   
  Creatures’ Tactics 
  Poison weirds are unique elemental creatures. 
  They won’t communicate, flee, surrender or take 
  captives. 
  Make the Poison Weird use Constrict against 
  nearest PC within reach and pull it into the pool. 
  Remember that Poisoned condition (PHB, p. 290) 
  gives Disadvantage to ability checks, so it will be 
  harder to escape grapple inside the pool. Take a 
  look to Suffocating rules (PHB, p. 183). 
    
  Area 23b 
  Encounter Difficulty 
  1 Night Hag (CR 5, MM, p. 176) = 2 PCs 
  Note. The Night Hag is weak opponent for 10th 
  level party. It is better to lure PCs to Area 23c and 
  join forces with Flesh Golems.  
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. As a DM you can decide that the Night 
  Hag emerging from Ethereal Plane (PHB, p. 300) 
  makes the party surprised. 
   
  Creatures’ Tactics 
  Evil night hags take perverse joy in corrupting 
  mortals. As intelligent creatures they can 
  negotiate, flee, surrender or take captives.  
   
  Make the Night Hag attack less-armored PC using 
  Claws. It can also cast Magic Missile to break 
  Concentration on spells or to reach PC in range. 
  Sleep spell casted on heavily wounded PC might 
  be brutal if Flesh Golems will be able to attack 
  Unconscious PC (PHB, p. 290). If you decide that 
  it’s time to flee make the Night Hag use 
  Etherealness. 
   
  Area 23c 
  Encounter Difficulty 
  4 Flesh Golems (CR 5, MM, p. 167) = 8 PCs 
  Note. These creatures are not going to attack 
  the party without reason. 
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. 
   
  
   
  Creatures’ Tactics 
  Golems are elemental spirits bound into material 
  form by powerful magic. They blindly obey any 
  commands of their creators, don’t feel pain and 
  don’t afraid of death. They won’t communicate, 
  flee or surrender. 
   
  Fire damage greatly decreases the Flesh Golem’s 
  combat effectiveness because of Aversion of Fire 
  trait. Make it focus on PCs who deal fire damage. 
  If the Golem goes Berserk and several creatures 
  are at the same range, you can roll a die to 
  determine random target. 
   
  Area 26b 
  Encounter Difficulty 
  1 Cloaker (CR 8, MM, p. 41) = 4 PCs 
   
  Surprise 
  Thanks to False Appearance trait the Cloaker 
  can surprise the party automatically. It is up to 
  DM if PCs can surprise the Cloaker. 
   
  Creatures’ Tactics 
  Cloakers are stealthy and patient underground 
  predators. They can communicate and flee but 
  won’t surrender or take captives. 
   
  The Cloaker has above-average Intelligence 
  score and can use advanced tactics. It easily 
  surprises the party because of False Appearance 
  trait. While the party is surprised make the 
  Cloaker use Phantasms. It is very good 
  defensive ability. Each time PC attacks the 
  Cloaker or uses harmful spell against it, roll a die 
  to determine the target. If it has 3 duplicates roll 
  d4, if 2 – roll d6 and divide result by 2, if one – 
  any die will work, you should only assign even or 
  odd number for the real Cloaker. Note, that 
  duplicate disappears only if it failed save against 
  damaging spell, but not when it takes damage on 
  successful save. After using Phantasms make the 
  Cloaker use Multiattack against less-armored 
  PC. With first successful Bite attack the Cloaker 
  attaches to the PC and gets Advantage on 
  subsequent Bite attacks. While attached to the PC 
  the Cloaker also gets only half damage because of 
  Damage Transfer trait and PC takes other half. 
  Successful Bite attack with Advantage inflicts 
  Blinded condition (PHB, p. 292) and PC can’t 
  breathe (PHB, p. 183). According to Jeremy 
  Crawford’s Twitter, PC can hold breath when 
  affected by such kind of abilities, which makes 
  them less dangerous. Moan doesn’t look like 
  effective attack, so it isn’t recommended to use it. 
   
  Area 27a 
  Encounter Difficulty 
  2 Barbed Devils (CR 5, MM, p. 66) = 4 PCs 
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. 
   
  Creatures’ Tactics 
  Devils are lawful evil fiends from lower plane 
  called Nine Hells (PHB, p. 300) collecting souls of 
  mortals. They can’t die on Material Plane, so they 
  won’t flee or surrender. They can take captives 
  and can communicate via Telepathy. 
   
  Make the Barbed Devil use Multiattack against 
  less armored PC. Use Hurl Flame only if there is 
  no chance to attack in melee. 
   
  Area 29 
  Encounter Difficulty 
  4 Helmed Horrors (CR 4, MM, p. 183, with 
  changes) = 4 PCs 
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. 
   
  Creatures’ Tactics 
  Helmed horrors are constructs with the ability to 
  reason and adjust their tactical decisions. They 
  won’t communicate, flee, surrender or take 
  captives. 
   
  
   
  The Helmed Horror can fly, so make them use 
  hit and run tactics. Use Multiattack against less-
  armored PC and stay in the air out of melee reach 
  between attacks. 
   
  Area 30 
  Encounter Difficulty 
  1 Efreeti (CR 11, MM, p. 183) = 7 PCs 
   
  Surprise 
  As a DM, you can decide that appearing Efreeti 
  makes the party surprised. It is up to DM if the 
  party can surprise the Efreeti. 
   
  Creatures’ Tactics 
  Efreet are masters of flame originating from 
  Elemental Plane of Fire (PHB, p. 300). They are 
  intelligent enough to communicate, flee, 
  surrender or take captives. 
   
  The Efreeti can fly, so it can use hit and run 
  tactics, staying out of melee reach between turns. 
  Make the Efreeti cast Wall of Fire targeting as 
  many PCs as possible at the beginning of the fight. 
  Next round make it use Multiattack against less 
  armored PC with strong ranged attacks. Use Hurl 
  Flame only if there is no chance to attack with 
  Scimitar. If Efreeti loses its Concentration on 
  Wall of Fire or the party is out of spell’s AoE, you 
  can make it cast Conjure Elemental. The Efreeti 
  has pretty high bonus to Con saves, so it won’t 
  lose control on Fire Elemental very fast. If you 
  decide that it’s time to flee, make the Efreeti cast 
  Invisibility and fly away. Note that Plane Shift 
  doesn’t work in Undermountain. 
   
  Area 34 
  Encounter Difficulty 
  1 Wyvern (CR 6, MM, p. 303) = 2 PCs 
   
  Surprise 
  As a DM, you can decide that reverting Wyvern 
  makes the party surprised. It is up to DM if the 
  party can surprise the Wyvern. 
  Creatures’ Tactics 
  Wyverns are distant relatives of true dragons. 
  They have low Intelligence score and aren’t able 
  to speak so they won’t negotiate, surrender or 
  take captives. They have instinct of self-
  preservation, so they can flee. 
   
  The Wyvern can fly and has 10 ft. Reach, which 
  allow it to use hit and run tactics, avoiding most 
  of opportunity attacks and staying out of melee 
  reach between turns. Make the Wyvern use 
  Multiattack against less armored PC with strong 
  ranged attacks. 
   
  Area 35 
  Encounter Difficulty 
  1 Archmage (CR 12, MM, p. 342, with changes) = 
  4 PCs 
  Note. This creature is not going to attack the 
  party without reason. 
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. 
   
  Creatures’ Tactics 
  This archmage is intelligent chaotic evil undead. 
  It is up to DM if it will negotiate, flee, surrender or 
  take captives. See Area 1a for its tactics. 
   
  Area 38 
  Encounter Difficulty 
  1 Shield Guardian (CR 7, MM, p. 183) = 3 PCs 
  1 Mage (CR 6, MM, p. 347) = 2 PCs 
  1 Grell (CR 3, MM, p. 183) = 1 PC 
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. 
   
  Creatures’ Tactics 
  Shield guardians are constructs created to protect 
  their masters. They can’t communicate and won’t 
  
   
  flee, surrender or take captives unless master 
  gives such an order. 
   
  Mage is intelligent enough to negotiate, flee, 
  surrender or take captives. 
   
  Grells are flying ambushers, who attacks 
  everything small enough to grab, paralyze, take 
  away and eat. They can flee and PCs can even 
  communicate with them under effect of the 
  Tongues spell. 
   
  The Shield Guardian’s Bound trait only works if 
  the Mage is within 60 ft., so it must always stay 
  within this distance. Spell Storing trait allows the 
  Shield Guardian cast 4th level spell in predefined 
  situations. As a DM, you decide what is the 
  situation and choose the spell, but it would be 
  logical if you choose it from Mage’s spellbook. 
  Greater Invisibility is great defensive spell and 
  FIreball is good AoE option. Make the Shield 
  Guardian use Multiattack against less armored, 
  Restrained or Paralyzed PC. Use Shield to protect 
  the Mage within 5 ft. 
   
  See Area 14 for Mage’s tactics. Don’t forget that 
  PC Paralyzed by the Grell fails Dexterity saves 
  automatically, for example against Fireball. 
   
  The Grell can fly speed and has attack with 10 ft. 
  Reach, which allow it to use hit and run tactics, 
  avoiding most of opportunity attacks and staying 
  out of melee reach between turns. Make the Grell 
  use Multiattack against less armored PC. 
  Successful Tentacles attack automatically inflicts 
  Grappled and Restrained conditions and 
  potentially Poisoned and Paralyzed (PHB, p. 290). 
  Restrained condition grants Advantage to all 
  attack rolls against PC and Paralyzed condition 
  automatically turns hits into Critical hits. The 
  Grell can drag Grappled victim without speed 
  penalty. 
   
  Area 44 
  Encounter Difficulty 
  1 Nycaloth (CR 9, MM, p. 311) = 5 PCs 
  2 Mezzoloths (CR 5, MM, p. 313) = 4 PCs 
  Surprise 
  Follow the standard procedure to determine 
  surprise 
   
  Creatures’ Tactics 
  All these creatures fight very well inside Cloudkill 
  spell’s AoE. See Area 4 and Area 13b for the 
  details. 
   
  Area 45a 
  Encounter Difficulty 
  1 Stone Golem (CR 10, MM, p. 167) = 6 PCs 
  Note. Ghostly skull with Initiative 30 in this 
  area can drop PCs Prone (PHB, p. 292), which 
  grants Advantage to Golem’s attack rolls. 
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. 
   
  Creatures’ Tactics 
  Golems are elemental spirits bound into material 
  form by powerful magic. They blindly obey any 
  commands given them by their creators, don’t 
  feel pain and don’t afraid of death. They won’t 
  communicate, flee, surrender or take captives.  
   
  Make the Stone Golem use Slow targeting as 
  many PCs as possible. Next round make it use 
  Multiattack against less-armored Prone PC. 
   
  Area 47b 
  Encounter Difficulty 
  1 Bone Devil (CR 9, MM, p. 66) = 5 PCs 
   
  Surprise 
  Follow the standard procedure to determine 
  surprise.  
   
  Creatures’ Tactics 
  Devils are lawful evil fiends from lower plane 
  called Nine Hells (PHB, p. 300) collecting souls of 
  mortals. They can’t die on Material Plane, so they 
  
   
  won’t flee or surrender. They can take captives 
  and can communicate via Telepathy. 
   
  The Bone Devil can fly and has 10 ft. Reach, 
  which allow it to use hit and run tactics, avoiding 
  most of opportunity attacks and staying out of 
  melee reach between turns. Make the Bone Devil 
  use Multiattack against less armored PC with 
  strong ranged attacks. The Bone Devil has decent 
  protection against spellcasters, so make it focus 
  on martial ranged PCs. 
  
SOURCE: textdata/thevault/Dungeons & Dragons [multi]/MGtCE of DotMM 1-23/Monsters' Guide to Combat Encounters - For Dungeon of the Mad Mage Level 9 - Dweomercore.pdf