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 creatures’ names 
  Italic style is used for the Spells. 
  Bold Italic style is used for the Abilities and Traits. 
  
   
  Level 1: Dungeon Level 
  This level is designed for four 5th 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 5th 
  level PCs. 
   
  Area 1 
  Encounter Difficulty 
  1 Bandit (CR 1/8, MM, p. 343) = 1 PC 
  Note. This Bandit is not going to fight, but 
  since PCs have an opportunity to notice his 
  presence, combat encounter may occur here. This 
  encounter is very easy but could be followed by 
  the harder one.  
   
  Surprise 
  The Bandit is not going to fight, so he won’t 
  surprise anyone. Use the standard procedure to 
  determine if PCs can surprise the Bandit. 
   
  Creatures’ Tactics 
  As intelligent creature, bandit can negotiate, flee 
  or surrender. 
   
  According to the book, the Bandit is hidden 
  behind the secret door and PCs can notice his 
  presence with successful DC 20 Wisdom 
  (Perception) check. It means that he doesn’t need 
  to roll Stealth. If they spot him, roll Initiative and 
  let PCs do whatever they want in initiative order, 
  so it will be easier for you to track all their 
  actions. Secret door could be found with the same 
  DC 20 Wisdom (Perception) check that is needed 
  to spot the Bandit. Since PCs starts from 5th level, 
  they might have Knock spell to open the door, 
  Gaseous Form to move through the hole or Misty 
  Step to teleport behind it. The Bandit should 
  spend his Action to use Dash and move to Area 
  6a. It is 80 ft. away from the secret door to Area 1, 
  so it will take minimum 2 rounds for the Bandit 
  to reach Area 6a. It is up to DM if sounds of the 
  battle, Knock spell or Bandit’s scream will bring 
  attention of other creatures who are residing in 
  Area 6c and 6d. If you decide so, they could reach 
  Area 6a in 2 rounds and the corridor connecting 
  Area 6a and Area 1 in 3 rounds. See their tactics 
  below at the respective area’s descriptions. 
   
  Area 2b 
  Encounter Difficulty 
  2 Intellect Devourers (CR 2, MM, p. 191) = 2 PCs  
  2 Bugbears (CR 1, MM, p. 33) = 1 PC 
  Note. These creatures are not going to fight.  
   
  Surprise 
  According to the book, these creatures are not 
  going to surprise PCs. It is impossible for PCs to 
  surprise this group because of Intellect 
  Devourer’s Detect Sentience ability. 
   
  Creatures’ Tactics 
  Mechanically, there are 4 creatures, but from 
  roleplaying perspective there are just two 
  Intellect Devourers inside Bugbears’ bodies. 
  There is not so much information about Intellect 
  Devourer’s tactics from the lore point of view. 
  Apart of Monster Manual, you can find some 
  additional information about this creature in 
  published books (WDH, p. 212 and VGTM, p. 77) 
  but there are no clues of how it fights. Intellect 
  Devourers have alien intelligence, so it is up to 
  DM if they will negotiate, flee, surrender or take 
  captives. 
   
  According to the book, PCs with Passive 
  Perception scores higher than Bugbears’ Stealth 
  roll could notice hiding or fleeing creatures. Note, 
  that the Bugbears are able to see PCs from 60 ft. 
  distance thanks to their Darkvision. If PCs are 
  using light sources, then the Bugbears can notice 
  them from 70 ft. when they enter Area 2a.  
   
  If PCs noticed the Bugbears and you want them 
  to flee, take a look to Chases rules (DMG, p. 252). 
  If you want them to fight, then use Morningstar 
  and focus on less-armored PCs within reach. 
   
  
   
  According to the book, Intellect Devourer 
  appears right after Bugbear’s death and act at 
  the same initiative count. Intellect Devourer’s 
  Multiattack includes Devour Intellect action. 
  From mechanical perspective it is represented 
  just as Intellect saving throw and it is up to you 
  how to describe this attack to your players. It 
  may look as telepathic blast or some kind of 
  hypnosis. Devour Intellect may inflict almost 
  permanent Stunned condition (PHB, p. 292) 
  because 5th level PCs usually don’t have access to 
  Greater Restoration spell. It is especially 
  dangerous for PCs with low Intelligence score. 
  Stunned condition includes Incapacitated 
  condition and allows the Devourer to use Body 
  Theft next round after successful Devour 
  Intellect. If PC will die because of Body Thief 
  ability Revivify and even Raise Dead spells will not 
  work, since 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. Note, that Body 
  Theft can be performed even in one round, if 
  several Devourers focus on one target. 
   
  Area 3 
  Encounter Difficulty 
  1 Psychic Gray Ooze (CR 1/2, MM, p. 243, with 
  changes) = 1 PC 
  Note. This Gray Ooze has optional Psychic 
  Crush ability. It is an interesting way to present 
  Undermountain augmented creature, but some 
  DM’s ruling is needed. 
   
  Surprise 
  The Gray Ooze is unnoticeable thanks to its False 
  Appearance trait. It means that the Ooze can 
  surprise PCs automatically and PCs don’t have 
  such opportunity. 
   
  Creatures’ Tactics 
  According to the lore, oozes are unintelligent 
  spawns of Demon Lord Juiblex. They don’t use 
  any tactics, they don’t surrender or flee, they just 
  attack everything they can eat. 
   
  If you decide that the Grey Ooze can use Psychic 
  Crush ability being motionless, then it will be 
  unnoticeable thanks to False Appearance. In this 
  case, the party could have hard time to 
  understand what’s going on and how to react 
  accordingly. If you decide that the Grey Ooze 
  can’t benefit from False Appearance trait while it 
  uses Psychic Crush, then the Ooze will have hard 
  time. Psychic Crush is the only ranged attack 
  option available for the Ooze and it is recharge-
  dependent ability. The Ooze also has no swim 
  speed which means it is limited to 5 ft. movement 
  per round and it won’t be able to attack anyone 
  out of this distance. You can make this combat 
  encounter less complicated if the Ooze will not 
  use Psychic Crush at all. Instead, make it stay 
  motionless near the statue until PC approaches to 
  its melee range and then attack with Pseudopod. 
  Note, that the Gray Ooze is Invisible (PHB, p. 
  291) underwater, so it has Advantage to attack 
  rolls. Target PC wearing metal armor. You 
  probably won’t be able to kill 5th level PC, but you 
  can make his or her armor less useful. Don’t 
  forget that Corrode Metal trait can damage 
  weapons. 
   
  Area 5 
  Encounter Difficulty 
  2 Grells (CR 3, MM, p. 172) = 4 PCs 
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. 
   
  Creatures’ Tactics 
  Grells are flying ambushers, who attacks 
  everything small enough to grab, paralyze, take 
  away and eat. They are intelligent enough to flee 
  and PCs can even communicate with them under 
  effect of the Tongues spell. 
   
  With 30 ft. fly speed and 10 ft. reach the Grells 
  probably will be able to reach and attack nearest 
  PCs starting round 1. Tentacles attack is pretty 
  nasty. If it hits, it automatically inflicts Grappled 
  and Restrained conditions and potentially 
  
   
  Poisoned and Paralyzed (PHB, p. 290-292). 
  Restrained condition grants Advantage to all 
  Grell’s attack rolls and Paralyzed condition 
  automatically turns hits into Critical hits. It is 
  optimal for the Grell to attack only one target at a 
  time. It can drag Grappled victim out of melee 
  reach without speed penalty. Ceiling in this room 
  is 50 ft. high, as mentioned in Undermountain 
  Overview chapter. 
   
  Area 6a 
  Encounter Difficulty 
  2 Doppelgangers (CR 3, MM, p. 82) = 4 PCs 
  1 Bandit Captain (CR 2, MM, p. 344) = 1 PC 
  7 Bandits (CR 1/8, MM, p. 343) = 1 PC 
  Note. This encounter occurs only if Bandit 
  from Area 1 had warned other Undertakers. 
  According to the book, they want 10 gp toll. 
   
  Surprise 
  These creatures want to talk so they are not going 
  to surprise PCs. Use standard procedure to 
  determine if PCs can surprise these creatures. 
   
  Creatures’ Tactics 
  As intelligent creatures the Undertakers can flee, 
  negotiate, surrender or take captives.  
   
  Put the Bandit Captain and the Doppelgangers 
  to the frontline because they are better in melee 
  and more durable than the Bandits. Save some 
  space between them because at 5th level PCs has 
  access to nasty AoE spells like Fireball and 
  Hypnotic Pattern. 
   
  Make the Bandit Captain and the 
  Doppelgangers use Multiattack and try to focus-
  fire less armored PCs. Don’t forget that the 
  Bandit Captain can use Parry once per round as 
  Reaction to avoid some damage from melee 
  attacks. 
   
  Spread the Bandits across the room at the 
  second line. Their Crossbow attacks are more 
  effective damage wise and range wise, so they 
  don’t need to be at the frontline. The Bandits are 
  smart enough to focus-fire less armored PCs. 
  Area 6c 
  Encounter Difficulty 
  1 Doppelganger (CR 3, MM, p. 82) = 2 PC 
  1 Bandit Captain (CR 2, MM, p. 344) = 1 PC 
  2 Bandits (CR 1/8, MM, p. 343) = 1 PC 
  Note. This encounter occurs if the Bandit from 
  Area 1 didn’t warn his allies and PCs was careful 
  enough not do it themselves. 
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. 
   
  Creatures’ Tactics 
  Follow the tactics described at Area 6a section. 
   
  According to WDMM, if the Bandit Captain takes 
  damage or sees any of his underlings killed, he 
  retreats to Area 7. The others flee to Area 8 and 
  team up with any Undertakers remaining there. 
   
  Area 6d 
  Encounter Difficulty 
  1 Doppelganger (CR 3, MM, p. 82) = 2 PCs 
  4 Bandits (CR 1/8, MM, p. 343) = 1 PC 
  Note. This encounter occurs if the Bandit from 
  Area 1 didn’t warn his allies and PCs was careful 
  enough not do it themselves.  
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. Note that at the first round of the 
  combat encounter surprised Bandits could still 
  be asleep (at least until their first turn starts, but 
  it is up to DM) which means that they are Prone 
  and Unconscious (PHB, p. 272). All attacks from 5 
  ft. will have Advantage and all hits become 
  Critical hits. Also, they will fail all Strength and 
  Dexterity saves automatically. 
   
  Creatures’ Tactics 
  See Area 6a. 
   
  
   
  Area 8a 
  Encounter Difficulty 
  1 Flesh Golem (CR 5, MM, p. 169) = 5 PCs 
  1 Doppelganger (CR 3, MM, p. 82) = 2 PCs 
  1 Bandit Captain (CR 2, MM, p. 344) = 1 PC 
  5 Bandits (CR 1/8, MM, p. 343) = 1 PC 
  Note. This combat encounter occurs only if PCs 
  were too loud or if the bandits from Area 6 
  reached this area in search of reinforcement. It 
  could be very tough fight for the party, especially 
  if weapon-dependent PCs don’t have magical or 
  adamantine weapons yet. According to the book, 
  the Undertakers demand 10 gp toll but it is up to 
  DM how would they react if PCs killed their allies 
  from Area 6. 
   
  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 or surrender. When its body is 
  heavily damaged the spirit tries to break free and 
  a golem goes berserk.  
   
  Fire damage decreases the Golem’s combat 
  effectiveness a lot because of Aversion of Fire 
  trait. Focus on PCs who deal fire damage. If the 
  Golem goes Berserk and several creatures are at 
  the same range, you could roll a die to determine 
  random target. 
   
  Tactics for the Bandit Captain, the Bandits and 
  the Doppelganger is described at Area 6a 
  section. 
   
  According to the book, the Bandit Captain will 
  flee to Area 7 when the Golem’s Berserk 
  activates. 
   
   
  Area 8b 
  Encounter Difficulty 
  1 Flesh Golem (CR 5, MM, p. 169) = 5 PCs 
  1 Bandit Captain (CR 2, MM, p. 344) = 1 PC 
  Note. This encounter may take place if PCs was 
  careful enough during their way through 
  Undertakers’ base.  
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. Note that at the first round of the 
  combat encounter, surprised Bandit Captain 
  could still be asleep (at least until her first turn 
  starts, but it is up to DM) which means that she is 
  Prone and Unconscious (PHB, p. 272). 
   
  Creatures’ Tactics 
  See Area 8a. 
   
  Area 8c 
  Encounter Difficulty 
  1 Doppelganger (CR 3, MM, p. 82) = 2 PCs 
  5 Bandits (CR 1/8, MM, p. 343) = 1 PC 
  Note. This encounter may take place if PCs was 
  good enough at Stealth during their way through 
  Undertakers’ base. 
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. 
   
  Creatures’ Tactics 
  See Area 6a. 
   
  Area 14b 
  Encounter Difficulty 
  1 Sahuagin Baron (CR 5, MM, p. 264) = 5 PCs 
  Note. This Sahuagin Baron lacks Trident 
  attack, so he deals less damage per round and 
  doesn’t have ranged attack options at all. 
   
   
  
   
  Surprise 
  As a DM, you can rule that reverting Sahuagin 
  Baron makes party surprised. It is also up to DM, 
  if PCs can surprise petrified Sahuagin Baron 
  somehow. 
   
  Creatures’ Tactics 
  According to MM, sahuagin are predatory race 
  who think of themselves as of rulers of the ocean 
  depths. To hunt other creatures is just a sport for 
  them. Smell of fresh blood drives them frenzy. 
  Barons are one of the most powerful creatures of 
  sahuagin kind. They are intelligent, so it is up to 
  DM if there is a possibility for surrender or 
  negotiations. 
   
  The Baron’s Blood Frenzy ability grants him 
  Advantage for all melee attacks against wounded 
  target. So, it is optimal for him to use Multiattack 
  against PC who started the combat encounter 
  with less than maximum hit points. It is up to DM 
  if the Baron can realize this fact. PHB suggests 
  that PCs above half of hp maximum usually don’t 
  show signs of injury (PHB, p. 197). 
   
  Area 16 
  Encounter Difficulty 
  3 Manticores (CR 3, MM, p. 213) = 6 PCs 
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. 
   
  Creatures’ Tactics 
  According to MM, manticores are familiar with 
  teamwork concept, despite their low Intelligence 
  score. They also can flee or negotiate, and they 
  know Common language. 
   
  It will be optimal for the Manticores to stay in 
  the air to avoid melee attacks and focus on less 
  armored PCs with their Tail Spike Multiattack. 
  According to the book, ceiling is 80 ft. high. The 
  room is big enough, so the Manticores are able to 
  spread to avoid AoE spells. 
   
  Area 17a 
  Encounter Difficulty 
  2 Giant Centipedes (CR 1/4, MM, p. 323) = 1 PC 
  Note. This combat encounter is not challenging 
  at all, so you can skip it to save some time of the 
  game session. 
   
  Surprise 
  As a DM you can rule that emerging Centipedes 
  makes party surprised. Follow the standard 
  procedure to determine surprise. 
   
  Creatures’ Tactics 
  Centipedes attack nearest creatures. You can roll 
  a die to choose random target, if several PCs are 
  at the same range. They can flee but can’t 
  surrender or communicate. 
   
  Area 17b 
  Encounter Difficulty 
  1 Black Pudding (CR 4, MM, p. 241) = 3 PCs 
   
  Surprise 
  As a DM, you can rule that awakening the 
  Pudding makes party surprised. It is also up to 
  DM if PCs could understand somehow that there 
  is the Pudding at the statue and if they could 
  surprise it. 
   
  Creatures’ Tactics 
  See Area 3 for some lore about oozes. 
   
  Corrosive Form ability harms any PC who 
  touches or attacks Pudding in melee and 
  damages metal and wooden weapons. Hope, in 
  your campaign PCs can fix it with Mending 
  cantrip. The Pudding attacks nearest creature. 
  You can roll a die to choose random target if 
  several PCs are at the same range. Successful 
  Pseudopod attack makes any non-magical armor 
  less effective. After PC makes successful attack 
  with slashing weapon or with the spell that deals 
  lightning damage Pudding will not take damage. 
  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 
  Puddings are not able to use Split ability, but 
  they are still immune to slashing and lightning 
  damage. 
   
  Area 18 
  Encounter Difficulty 
  1 Troll (CR 5, MM, p. 291) = 5 PCs 
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. Note that Keen Smell trait gives +5 to 
  the Troll’s Passive Perception score (see Passive 
  Checks, PHB, p. 175). 
   
  Creatures’ Tactics 
  Trolls eat anything they can catch and devour. It 
  is up to DM if troll will negotiate, flee or 
  surrender. 
   
  The Troll has only Multiattack, so just attack less 
  armored PC, ignoring any opportunity attacks. 
  While Regeneration trait is active, Troll have no 
  reason to worry about damage taken. PCs will not 
  be able to kill the Troll without fire or acid 
  damage source. If the Troll takes acid or fire 
  damage from any PC make him focus on that 
  particular PC. 
   
  Area 21 
  Encounter Difficulty 
  2 Shadowy Duplicates (CR 1/2, MM, p. 269, with 
  changes) = 1 PC 
  Note. This encounter is not very challenging if 
  more than one PC present. You can skip it to save 
  some time. 
   
  Surprise 
  As a DM, you can rule that emerging Duplicates 
  make party surprised. There is no way for the 
  party to surprise the Duplicates. 
   
  Creatures’ Tactics 
  If you want to make this combat encounter a bit 
  more challenging let the Duplicates attack only 
  their creator. They won’t flee, negotiate or 
  surrender. 
   
  Strength Drain attack may force PC to take Short 
  Rest, or if the Duplicates will have lucky rolls 
  even kill PC with low Strength score. If the party 
  don’t use light sources, use Shadow Stealth 
  ability before the attack to get Advantage. 
   
  Area 23 
  Encounter Difficulty 
  4 Intellect Devourers (CR 2, MM, p. 191) = 4 PCs 
  4 Bugbears (CR 1, MM, p. 33) = 2 PCs 
  15 Goblins (CR 1/4, MM, p. 165) = 2 PCs 
  Note. This encounter may take place if the 
  Bugbears from Area 2b managed to reach Area 
  23 and you decided that all these creatures set up 
  an ambush or want to negotiate.  
   
  Surprise 
  As a DM, you should decide if these creatures set 
  up an ambush and try to surprise the party or 
  they meet them openly and negotiate for safe 
  passage. It is impossible to surprise these 
  creatures because of Intellect Devourer’s Detect 
  Sentience trait.  
   
  Creatures’ Tactics 
  There are two points where these creatures can 
  meet or ambush the party: Area 25b and corridor 
  leading to the south from Area 21. 
   
  See Area 2b for the information about Intellect 
  Devourers and the Bugbears 
   
  According to VGTM, all goblinoids hate servants 
  of other gods, because they believe that their god 
  Maglubiyet is the only true god. As intelligent 
  creatures they can flee, negotiate or surrender. 
   
  Make Goblins use their Shortbow attacks against 
  less-armored PCs. You can make the Goblins 
  focus on paladins or clerics. Note that without 
  
   
  shields Goblins’ AC is 13. If you decide that there 
  are some places where goblins can hide to get 
  Advantage, they can do it as Bonus Action 
  because of Nimble Escape trait. If PCs approach 
  to melee range use Disengage as Bonus Action to 
  run away and attack with Shortbow after that. 
   
  Area 23a 
  Encounter Difficulty 
  6 Goblins (CR 1/4, MM, p. 165) = 1 PC 
  Note. This encounter may take place if the 
  Bugbears from Area 2b didn’t managed to reach 
  Area 23 and Intellect Devourers from Area 23b 
  does nothing when detect approaching PCs.  
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. 
   
  Creatures’ Tactics 
  The best solution for the Goblins is to raise alarm 
  at the camp. See Area 23 if they are brave enough 
  to fight. According to the book, if all Bugbears 
  are killed, the Goblins flee to Area 28. 
   
  Area 23b 
  Encounter Difficulty 
  2 Intellect Devourers (CR 2, MM, p. 191) = 2 PCs 
  2 Bugbears (CR 1, MM, p. 33) = 1 PC 
  Note. This encounter may take place if the 
  Bugbears from Area 2b didn’t managed to reach 
  Area 23 and the Intellect Devourers does 
  nothing when detect approaching PCs. 
   
  Surprise 
  It is impossible to surprise these creatures 
  because of Intellect Devourer’s Detect 
  Sentience trait. Follow the standard procedure to 
  determine if these creatures could surprise the 
  party. 
   
  Creatures’ Tactics 
  See Area 2b. 
   
  Area 23c 
  Encounter Difficulty 
  9 Goblins (CR 1/4, MM, p. 165) = 2 PCs 
  Note. This encounter may take place if the 
  Bugbears from Area 2b didn’t managed to reach 
  Area 23 and Intellect Devourers from Area 23b 
  does nothing when detect approaching PCs. 
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. 
   
  Creatures’ Tactics 
  The best solution for the Goblins is to raise alarm 
  at the camp. See Area 23 if they are brave enough 
  to fight. According to the book, if all Bugbears 
  are killed, the Goblins flee to Area 28. 
   
  Area 26c 
  Encounter Difficulty 
  1 Gelatinous Cube (CR 2, MM, p. 242) = 1 PC 
  Note. This is easy encounter but it can be 
  interesting for your players because of Cube’s 
  abilities. 
   
  Surprise 
  According to the book, PCs can notice the Cube if 
  they have Passive Perception 15 or higher. 
  Otherwise they are surprised. For PCs follow the 
  standard procedure to determine surprise. 
   
  Creatures’ Tactics 
  See Area 3 for the information about oozes. 
   
  Pseudopod is pretty simple ability and you 
  should use it only for opportunity attacks. Since 
  the combat encounter takes place at 10 ft. wide 
  corridor the Cube can move 15 ft. forward during 
  Engulf attack and force all PCs on its way to make 
  up to three Dexterity saving throws (once per 5 
  ft.). Note, that you can use Cube’s regular 15 ft. 
  movement to move closer to PCs, but this 
  movement don’t allow to enter PC’s space. Don’t 
  forget that since PC can’t stop at the space of 
  
   
  another PC, he or she can be engulfed even with 
  successful saving throw. It is up to DM, if PC who 
  can’t breathe is able to cast spells with verbal 
  component. The other important thing is that PC 
  can’t regain hp if he or she is dying because of 
  Suffocating (PHB, p. 183). 
   
  Area 28a 
  Encounter Difficulty 
  2 Bugbears (CR 1, MM, p. 33) = 1 PC 
  Note. According to the book, the Bugbears are 
  not going to fight here. They move to Area 28b to 
  ambush the party with all forces available. 
   
  Surprise 
  The Bugbears are not going to surprise anyone. 
  Follow the standard procedure to determine if 
  the Bugbears are surprised. 
   
  Creatures’ Tactics 
  Fight for bugbears is kind of religious service. 
  They fight ferociously, they love the slaughter and 
  retreat is a big shame for them, but still is an 
  option. They also can negotiate in Common and 
  Goblin languages. Like all goblinoids, bugbears 
  hate clerics and paladins so you can make them 
  focus on such PCs first. 
   
  If the Bugbears will be surprised by PCs, they can 
  try to call for help of the Goblins opening the 
  door to Area 28b. It is possible that PCs will be 
  able to kill or disable the Bugbears before they 
  take first turn if they use spells like Hypnotic 
  Pattern or Fireball and it is up to DM, if the 
  Goblins at Area 28c will hear something. See 
  Area 2b for Bugbear’s tactics. 
   
  Area 28b 
  Encounter Difficulty 
  2 Bugbears (CR 1, MM, p. 33) = 1 PC 
  6 Goblins (CR 1/4, MM, p. 165) = 1 PC 
  Note. This encounter takes place if the 
  Bugbears from Area 28a was able to reach this 
  area. 
  Surprise 
  Follow the standard procedure to determine 
  surprise. 
   
  Creatures’ Tactics 
  See Area 23. 
   
  Area 28c 
  Encounter Difficulty 
  6 Goblins (CR 1/4, MM, p. 165) = 1 PC 
  Note. Without Bugbears from Area 28a this 
  encounter is too easy. You can skip it. 
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. 
   
  Creatures’ Tactics 
  According to the book, the Goblins are not 
  willing to fight without their Bugbear masters. If 
  combat encounter occurs, you can use the 
  guidance detailed at Area 23 section. 
   
  Area 30 
  Encounter Difficulty 
  1 Air Elemental (CR 5, MM, p. 123) = 5 PCs 
   
  Surprise 
  According to the book, the Air Elemental is not 
  going to hide. The Air Elemental senses door 
  opening because of air pressure change, so there 
  is no chance to surprise it. 
   
  Creatures’ Tactics 
  The Air Elemental is berserk which means it 
  won’t negotiate, flee, surrender or take captives.  
   
  Make it enter as much PCs’ spaces as possible, 
  don’t pay attention to opportunity attacks and 
  use the Whirlwind. Roll d8 to determine the 
  direction where unlucky PCs will be thrown and 
  if they strike the wall or another PC deal 
  additional damage. If Whirlwind is unavailable 
  
   
  because of the recharge just Slam nearest PC. If 
  several creatures are at the same range, you can 
  roll a die to determine random target. 
   
  Area 31 
  Encounter Difficulty 
  1 Wererat (CR 2, MM, p. 209) = 1 PC 
  Note. Wererat don’t have weapons and 
  according to the Monster Manual, they use Bite 
  only to transmit lycanthropy to creatures they 
  want to induct into their clan. 
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. Note that Keen Smell trait gives +5 to 
  the Wererat’s Passive Perception score (see 
  Passive Checks, PHB, p. 175). 
   
  Creatures’ Tactics 
  As intelligent creatures, wererats can negotiate, 
  flee or surrender.  
   
  The Wererat has no effective attacks and won’t 
  fight. If fight occur, it will flee to Area 35. Take a 
  look to the Chases rules (DMG, p. 252) if 
  appropriate. 
   
  Area 35 
  Encounter Difficulty 
  1 Wererat (CR 2, MM, p. 209) = 1 PC 
  10 Giant Rats (CR 1/8, MM, p. 327) = 1 PC 
  Note. If the Wererat from Area 31 managed to 
  reach this area add it to these creatures. 
  Encounter still won’t be challenging because 
  according to the book, the Wererat is going to 
  flee as fast as possible but as a DM, you can let it 
  fight or you can skip this combat encounter. 
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. Note that Keen Smell trait gives +5 to 
  the Wererat’s Passive Perception score (see 
  Passive Checks, PHB, p. 175). 
  Creatures’ Tactics 
  As intelligent creatures, wererats can negotiate, 
  flee or surrender.  
   
  Rats are animals, so they can’t surrender, take 
  captives or communicate without Speak with 
  Animals spell or similar abilities, but they can flee. 
   
  If you decide to make Wererats fight, keep the 
  distance and use Hand Crossbow attacks against 
  less-armored PCs within reach. Focus on spell-
  casters or PCs with magical or silvered weapons. 
   
  The Giant Rats has Pack Tactic trait, so the best 
  solution is to focus on one or two nearest PCs. 
   
  Area 36a 
  Encounter Difficulty 
  2 Gricks (CR 2, MM, p. 173) = 2 PCs 
  Note. This is easy encounter, so you can skip it. 
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. Thanks to Stone Camouflage trait the 
  Gricks have advantage on Stealth rolls. 
   
  Creatures’ Tactics 
  According to MM, gricks are not very intelligent. 
  They don’t work together and will attack nearest 
  target available. They can’t communicate or 
  surrender, but they can flee. 
   
  Note, that Beak attack is only available if the 
  Grick hit with Tentacles attack. And don’t forget 
  about resistance to non-magical weapons. 
   
  Area 36b 
  Encounter Difficulty 
  5 Gricks (CR 2, MM, p. 173) = 5 PCs 
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. Thanks to Stone Camouflage trait the 
  Gricks have advantage on Stealth rolls. 
  
   
  Creatures’ Tactics 
  See Area 36a. 
   
  Area 36c 
  Encounter Difficulty 
  1 Grick Alpha (CR 7, MM, p. 173) = 7 PCs 
  Note. This creature is not going to fight, but if 
  PCs will provoke it this could be a very dangerous 
  encounter. 
   
  Surprise 
  The Grick is not going to surprise PCs. Follow the 
  standard procedure to determine if PCs could 
  surprise it.  
   
  Creatures’ Tactics 
  Gricks can’t negotiate, take captives or surrender, 
  but they can flee. 
   
  The Grick Alpha is not very intelligent, so just 
  make it use Multiattack against nearest target.  
   
  Area 37 
  Encounter Difficulty 
  1 Revenant (CR 5, MM, p. 259) = 5 PCs 
  Note. A Revenant does nothing special if the 
  creatures it fights are not its sworn enemies so 
  encounter will be easier than XGE suggest. 
   
  Surprise 
  Revenant itself is not trying to hide, since it isn’t 
  planning to fight with the party. Follow the 
  standard procedure to determine if PCs could 
  surprise it.  
   
  Creatures’ Tactics 
  According to the book, the Revenant is seeking 
  revenge to his previous party members. If for 
  some reasons fight will occur the Revenant will 
  be able to use only Multiattack option and will 
  deal no extra damage. However, nothing can stop 
  you as a DM, to make the party its sworn enemies 
  and use Vengeful Glare in combat and Vengeful 
  Tracker after Rejuvenation. It could be fun to 
  make the Revenant following the party through 
  23 levels of the dungeon. 
   
  Area 39a 
  Encounter Difficulty 
  2 Ettins (CR 4, MM, p. 132) = 6 PCs 
  1 Intellect Devourer (CR 2, MM, p. 191) = 1 PC 
  3 Bugbears (CR 1, MM, p. 33) = 2 PCs 
  19 Goblins (CR 1/4, MM, p. 165) = 3 PCs 
  1 Shrieker (CR 0, MM, p. 138) = 1 PC 
  Note. Thanks to the Intellect Devourer’s 
  Detect Sentience trait these creatures will most 
  probably notice PCs from 300 ft. range because at 
  5th level they don’t have reliable access to Mind 
  Blank spell. It is up to DM how would these 
  creatures react, because there are no suggestions 
  in the book. Of course, they don’t know who 
  exactly approaches but it seems logical for these 
  creatures to prepare somehow. According to Map 
  Travel Pace table (DMG, p. 242), PCs moving with 
  normal speed will cover 300 ft. of dungeon in 1 
  minute. It is enough time for some preparations. 
  There is also Shrieker mentioned in Area 39 
  description, but it is not mentioned anywhere 
  else. Since the only entrance located in Area 39a 
  you can place it there. If you decide that all 
  monsters will meet the party in Area 39a you can 
  follow the guidance below. Note that these 
  creatures can overwhelm the party. 
   
  Surprise 
  If you decide that only the Shrieker present in 
  this room don’t forget that it is indistinguishable 
  from an ordinary fungus thanks to False 
  Appearance trait.  If you decide that other 
  creatures hiding here, follow the standard 
  procedure to determine surprise for PCs. Thanks 
  to Detect Sentience trait, it is impossible for PCs 
  to surprise these creatures.  
   
  Creatures’ Tactics 
  All these creatures are intelligent so they can 
  communicate, flee, surrender or take captives.  
   
  Ettins are simple monsters. Use Multiattack 
  against nearest PC. If you want to make 
  
   
  encounter a bit easier you can make the Ettin 
  fight two PCs simultaneously. You can even make 
  its two heads argue on whom do they want to kill 
  first. 
   
  See Area 2b for the information about the 
  Intellect Devourer and the Bugbears. 
   
  See Area 23 for the information about the 
  Goblins.  
   
  The Shrieker has no attack options but it can 
  Shriek every turn which is fun. 
   
  Area 39b 
  Encounter Difficulty 
  1 Intellect Devourer (CR 2, MM, p. 191) =1 PC 
  3 Bugbears (CR 1, MM, p. 33) = 2 PCs 
  Note. This encounter may take its place, if you 
  decide that the Intellect Devourer is not going to 
  call all allies available in the outpost when it will 
  notice approaching PCs. 
   
  Surprise 
  Thanks to Detect Sentience trait it is impossible 
  for PCs to surprise these creatures. Follow the 
  standard procedure to determine surprise for 
  PCs. 
   
  Creatures’ Tactics 
  See Area 2b. 
   
  Area 39c 
  Encounter Difficulty 
  19 Goblins (CR 1/4, MM, p. 165) = 3 PCs 
  Note. This encounter can take place if you 
  decide that the Bugbears from Area 39b didn’t 
  call the Goblins and they react to the sounds of 
  the battle at Area 39b or Shriek from Area 39a. 
  According to their speed, the Goblins can reach 
  Area 39a in 2 rounds and Area 39b in 3 rounds. 
   
   
   
  Surprise 
  Follow the standard procedure to determine 
  surprise. 
   
  Creatures’ Tactics 
  See Area 23. 
   
  Area 39d 
  Encounter Difficulty 
  2 Ettins (CR 4, MM, p. 132) = 6 PCs 
  Note. This encounter may take place if you 
  decide that the Bugbears from Area 39b didn’t 
  call the Ettins and they react to the sounds of 
  battle. According to their speed, the Ettins can 
  reach Area 39c in 1 round, Area 39a in 2 rounds 
  and Area 39b in 3 rounds. 
    
  Surprise 
  Follow the standard procedure to determine 
  surprise. Note that Two Heads trait gives +5 to 
  the Ettin’s Passive Perception score (see Passive 
  Checks, PHB, p. 175). 
   
  Creatures’ Tactics 
  See Area 39a.  
   
  Area 40 
  Encounter Difficulty 
  1 Large Mimic (CR 4, MM, p. 220, with changes) 
  = 1 PC 
    
  Surprise 
  Thanks to False Appearance trait the Mimic will 
  easily surprise the party. It is up to DM, if the 
  party have a chance to surprise it. 
   
  Creatures’ Tactics 
  According to MM, in most cases mimics have only 
  predatory intelligence and won’t negotiate, flee 
  or surrender. 
   
  
   
  Wait for a curious PC to touch the Mimic and 
  activate Adhesive trait. Roll initiative. Use Bite 
  with Advantage thanks to Grappler trait to deal 
  as much damage as you can. 
   
  Area 41 
  Encounter Difficulty 
  20 Stirges (CR 1/8, MM, p. 284) = 2 PCs 
    
  Surprise 
  Follow the standard procedure to determine 
  surprise. 
   
  Creatures’ Tactics 
  It is up to DM if stirges have the instinct of self-
  preservation and can flee. They can’t take 
  captives, communicate or surrender. 
   
  The Stirges have only Blood Drain attack and 
  don’t have enough Intelligence to use any kind of 
  tactics, so make them focus on nearest PC. 
  
SOURCE: textdata/thevault/Dungeons & Dragons [multi]/MGtCE of DotMM 1-23/Monsters' Guide to Combat Encounters - For Dungeon of the Mad Mage Level 1 - Dungeon Level.pdf