Boss Monster: THE DUNGEON MASTER HIMSELF

Hey there friends! It is time. The party has journeyed deep into the bowels of the mythic underground and overcome countless challenges. Here, in the surreal core of the supernatural being that is the dungeon, the party has finally found their quarry. The true enemy, the entity which has plagued them with myriad traps, puzzles, and monsters. The source of all the evil that swells from the deeps.

It is time to face THE DUNGEON MASTER.

NPC: Nemazys

Monster: Dungeon Master

Templates Used: Mind Flayer (Arcanist), Half-Black-Shadow-Dragon, Lich, Vampire

Medium Undead (Shapechanger), Lawful Evil

AC 15
HP 71 (13d8+13)
SPD 30

STR 18 +4
DEX 18 +4
CON 18 +4
INT 19 +4
WIS 17 +3
CHA 17 +3

Saves:
INT+7
WIS+6
CHA+6

Skills:
Arcana+7
Deception+6
Insight+6
Perception+6
Persuasion+6
Stealth+8

Resistances:
Acid
Cold
Lightning
Necrotic

Damage Immunities:
Poison
Mundane Bludgeoning
Mundane Piercing
Mundane Slashing

Condition Immunities:
Charmed
Exhaustion
Frightened
Paralyzed
Poisoned

Senses:
Darkvision 120
Blindsight 10
Truesight 120

Languages:
Deep Speech
Undercommon
Telepathy 120ft
*Qualith
Draconic
Common
Abyssal
Infernal
Primordial
Orc
Goblin

Challenge 24

TRAITS

Vampiric Weaknesses: Cannot enter a residence without invitation. 20 acid dam from running water. If wood pierces its heart, paralyzed until wood is removed. 20 radiant damage and disadvantage on attacks and ability checks in sunlight.

Sunlight Sensitivity: While in sunlight, disadvantage on attack rolls and vision-related perception checks.

Legendary Resistance (3/day): On failed save, succeed.

Magic Resistance: Advantage on saves against spells and magical effects.

Turn Resistance: Advantage on saves against turn undead.

Regeneration: @ turn start: if HP > 1 and no sunlight or running water: +20hp. If damaged by radiant damage, or damage from holy water, this trait ceases to function for 1 turn.

Misty Escape: @ 0hp, automatically uses shapechanger trait to change into mist form, does not become unconscious. It must return to its resting place within 2 hours or will dissipate, and its body is destroyed. It returns to its normal form at 0hp and stable upon returning to its resting place, and regains 1hp after a short rest. If it cannot shapechange (sunlight or water) its body is destroyed.

Rejuvination: If phylactery exists, lich does not make death saves at 0hp, even if its body is destroyed, instead regaining a new body within 5ft of its phylactery in 1d10 days.

Shapechanger: When not in sunlight or running water, 1 Action: change statblock to tiny bat, or become a medium cloud of mist, or back to its true form. Reverts to true form on death. While in mist form, the only action it can take is the move action, has a hover speed of 20ft, has infinitely small squeeze space, can enter any other creature's space and end its turn there, has advantage on all physical saves, and is immune to all mundane damage, but cannot pass through water.

Living Shadow: While in dim light or darkness, resistance to all but force, spychic, and radiant damage.

Shadow Stealth: While in dim light or darkness, can take the hide action as a bonus action.

Spider Climb: No checks or saves to climb any solid surface.

Innate Spellcasting (Psionics): Spellcasting ability is INT, spell save DC 15.
Spell List:
At-Will:
Detect Thoughts
Levitate
1/day:
Dominate Monster
Plane Shift (Self Only)

Spellcasting: 18th-level caster, spellcasting ability is INT, spell save DC is 20, spell attack +12, wizard spell list.
L0:
Blade Ward
Dancing Lights
Mage Hand
Shocking Grasp
Prestidigitation
Ray of Frost
L1 (4):
Detect Magic
Disguise Self
Magic Missile
Shield
Sleep
Thunderwave
L2 (3):
Blur
Invisibility
Melf's Acid Arrow
Mirror Image
Ray of Enfeeblement
L3 (3):
Animate Dead
Clairvoyance
Counterspell
Dispel Magic
Fireball
Lightning Bolt
Sending
L4 (3):
Blight
Confusion
Dimension Door
Hallucinatory Terrain
L5 (3):
Cloudkill
Scrying
Telekinesis
Wall of Force
L6 (1):
Disintegrate
Globe of Invulnerablity
L7 (1):
Finger of Death
Plane Shift
L8 (1):
Dominate Monster
Power Word Stun
L9 (1):
Power Word Kill

Pseudodragon Familliar: The pseudodragon has a magic, telepathic bond. While the two are bonded, the companion can sense what the pseudodragon senses as long as they are within 1 mile of each other. While the pseudodragon is within 10 feet of its companion, the companion shares the pseudodragon's Magic Resistance trait. At any time and for any reason, the pseudodragon can end its service as a familiar, ending the telepathic bond.

ACTIONS

Multiattack: Makes two attacks in 1 attack action. Only one may be the Bite attack.

Unarmed Strike: The vampire makes an unarmed strike or graple attack. If the vampire has a weapon equipped, they will use that weapon instead.

Bite: MWA: +9 ATK, @ 5ft, 1 target that must be willing, grappled, incapacitated, or restrained, HIT: 7(1d6+4) pi dam + 10(3d6) permanent nec dam, vampire gains hp equal to permanent dam dealt to target. The permanent damage is healed with a long rest. Creatures are instantly killed if their hp drops to 0 from permanent damage. Creatures buried with 0 maximum hp rise the following night as a vampire spawn in the vampire's direct control.

Tentacles: MWA: +7 ATK, @ 5ft, 1 target, HIT: 15(2d10+4) psi dam, targets < large auto-grappled w. DC15 INT save or be stunned until his grapple ends.

Extract Brain: MWA: Target must be incapacitated and grappled by this creature in its natural form. +7 ATK, @ 5ft, HIT: 55(10d10) pi dam, if target @ 0hp, target dies, no save.

Mind Blast: (Recharge 5-6): @ 60ft cone, targets make DC15 INT save vs. 22(4d8+4) psi dam and 1 min stun, with rethrow at each turn end to end effect.

Shadow Breath (Recharge 5-6): @ 5x15ft cone, targets make DC11 DEX save vx. 22(5d8) nec dam, HIT: half dam. Targets reduced to 0hp by this attack die, no save, returns as undead shadow under its control.

Paralyzing Touch: MSA: +12 ATK, @5ft, 1 target, HIT: 10(3d6) cold dam, DC18 CON save vs. paralyzed 1 min. w. rethrow at each turn end to end effect.

Charm:

Children of the Night: 1/day; 2d4 swarm of bats, 2d4 swarm of rats, or 3d6 wolves when outdoors; at night; acting as allies and obeying spoken commands; 1 min or until dismissed or this creature's death.

LEGENDARY ACTIONS

Up to 3 AP, chosen from this list, at the end of turn.

Move(1): Moves up to SPD without provoking opportunity attacks.

Unarmed Strike(1): Uses unarmed strike action.

Bite(2): Uses bite action.

Cantrip(1): Casts a cantrip.

Paralyzing Touch(2): Uses paralyzing touch action.

Frightening Gaze(2): @ LOS 10ft, 1 target, DC18 WIS save vs. frightened 1 min. w. rethrow at each turn end to end effect. When this effect ends on an affected target, they are immune to this legendary action and its effect for 1 day.

Disrupt Life(3): @ 20ft sphere, all targets, DC18 CON save vs. 21(6d6) nec dam, HIT: half dam.

LAIR ACTIONS

When in lair, on init # 20, gets 1 lair action, actions can not be used twice in a row.

* Pools of water @ LOS 120ft surge outward in a agrasping tide. All targets within 20ft of such pools make DC15 STR save vs. being moved into pool and knocked prone.

* 20ft sphere of insect swarms @ 120ft, all targets DC 15 CON save vs. 10(3d6) pi dam, HIT: half dam. Remains until dismissed, replaced by this action again, or death.

* 15ft magical darkness @ 60ft. Remains until dismissed, replaced by this action again, or death.

* Regain 1 spell lot of level 1d8

* 1 target, @ LOS 30ft, forms a tether of negative energy with target. Whenever it takes damage, target makes DC18 CON save vs. splitting damage between the two.

* Calls out for the spirits of the lair to attack, 1 target, @ LOS 50ft, DC18 CON save vs. 52(15d6) nec dam, HIT: half dam.

LAIR EFFECTS

Plants within 500ft of lair wither, becoming twisted an thorny.

Shadows cast within 500ft of lair become unusual, and sometimes independently mobile.

Land within 6 miles of lair takes twice as long to travel through, since the plants grow thick and twisted, and the swamps are dense with reeking mud.

Water sources within 1 mile of lair are supernaturally fouled. Enemies of the dungeonmaster regurgitate such water within minutes.

Fog lightly obscures the land within 6 miles of lair.

The fog within 500ft of lair occasionally takes eerie forms, such as grasping claws and writhing serpents.

Noticable increase of bats and rats in region.