Shadar-kai Soul Monger

Medium Humanoid (Elf), Neutral Evil

STR
8 (-1)
DEX
17 (+3)
CON
14 (+2)
INT
19 (+4)
WIS
16 (+3)
CHA
13 (+1)
Fey Ancestry.

The shadar-kai has advantage on saving throws against being charmed, and magic can't put it to sleep.

Magic Resistance.

The shadar-kai has advantage on saving throws against spells and other magical effects.

Soul Thirst.

When it reduces a creature to 0 hit points, the shadar-kai can gain temporary hit points equal to half the creature's hit point maximum. While the shadar-kai has temporary hit points from this trait, it has advantage on attack rolls.

Weight of Ages.

Any Beast or Humanoid (except an elf) that starts its turn within 5 feet of the shadar-kai has its speed reduced by 20 feet until the start of that creature's next turn.

Spellcasting.

The shadar-kai casts one of the following spells, requiring no material components and using Intelligence as the spellcasting ability (spell save DC 16):

1/day each: bestow curse, finger of death, gaseous form, seeming

Actions

Multiattack.

The shadar-kai makes two Shadow Dagger attacks.

Shadow Dagger.

Melee or Ranged Weapon Attack: +7 to hit, reach 5 ft. or range 20/60 ft., one target. Hit: 13 (4d4 + 3) piercing damage plus 19 (3d12) necrotic damage, and the target has disadvantage on saving throws until the end of the shadar-kai's next turn. The dagger magically returns to the shadar-kai's hand immediately after a ranged attack.

Wave of Weariness (Recharge 4-6).

The shadar-kai emits weariness in a 60-foot cube. Each creature in that area must make a DC 16 Constitution saving throw. On a failed save, a creature takes 45 (10d8) psychic damage and suffers 1 level of exhaustion. On a successful save, it takes half as much damage and doesn't gain a level of exhaustion.

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Shadar-kai Soul Monger

Source: Mordenkainen Presents: Monsters of the Multiverse, p. 214 - Licenses and attribution