Demilich

+6

Arcana: The monster's treasure hoard features magic items with the noted theme. The Dungeon Master's Guide details treasure hoards appropriate for each theme.

If the demilich fails a saving throw, it can choose to succeed instead.

4/DAY

If the demilich is destroyed, it reforms and regains all its Hit Points in 1d10 days unless a Wish spell is cast on its remains.

The demilich makes three Necrotic Burst attacks.

Melee or Ranged Attack Roll: +11, reach 5 ft. or range 120 ft. Hit: 24 (7d6) Necrotic damage.

Constitution Saving Throw: DC 19, each creature in a 30-foot Emanation originating from the demilich. Failure: 70 (20d6) Psychic damage. Failure or Success: The target has the Frightened condition until the start of the demilich's next turn.

D5

The Demilich can take 3 legendary actions, choosing from the options below. Only one legendary action can be used at a time and only at the end of another creature's turn. The Demilich regains spent legendary actions at the start of its turn.

3/TURN

Constitution Saving Throw: DC 19, one creature the demilich can see within 120 feet. Failure: The target's Hit Point maximum decreases by 14 (4d6). Failure or Success: The demilich can't take this action again until the start of its next turn.

The demilich flies up to its Fly Speed, shedding grave dust. Each creature within 5 feet of the demilich as it moves is targeted once by the following effect. Constitution Saving Throw: DC 19. Failure: The target has the Blinded condition until the end of the demilich's next turn. Failure or Success: The demilich can't take this action again until the start of its next turn.

The demilich makes one Necrotic Burst attack.

Demiliches jealously guard their deathtrap-laden sanctums. The most notorious of these is the Tomb of Horrors, lair of the infamous Acererak. The region containing a demilich's lair is twisted by its presence, creating the following effects:

Enervating Domain: Whenever a creature other than the demilich or one of its allies finishes a Long Rest within 1 mile of the lair, the creature must succeed on a DC 20 Constitution saving throw or have its Hit Point maximum reduced by 1d4. This reduction lasts until the creature finishes a Long Rest outside that area.

Travel Ward: Creatures can't use teleportation or planar travel to enter or exit the lair.

If the demilich dies or moves its lair elsewhere, these effects end immediately.