Lohezet

Lohezet ignores a creature's resistance to poison damage.

Lohezet makes three Withering Blast attacks and uses Miasma if it's available. He can replace one of the attacks with a use of Spellcasting.

Melee or Ranged Spell Attack Roll: +9 to hit, reach 5 ft. or range 60 ft., one target. Hit: 18 (2d12 + 5) necrotic damage.

Lohezet magically conjures a billowing cloud of purple fog in a 20-foot-radius sphere centered on a point within 120 feet of himself. The area within the sphere is Vision and Light, and when a creature starts its turn in the sphere or enters the sphere for the first time on a turn, it must make a DC 17 Constitution saving throw. On a failed save, the creature takes 39 (6d12) poison damage and is poisoned until the start of its next turn. On a successful save, the creature takes half as much damage and isn't poisoned. The cloud lasts for 1 minute, until Lohezet ends it early (no action required), or until Lohezet uses this action again. A strong wind disperses the cloud.

When a creature within 60 feet of Lohezet damages him, Lohezet magically retaliates with a spray of foul, purple mist. The creature must make a DC 17 Constitution saving throw, taking 16 (2d10 + 5) poison damage on a failed save, or half as much damage on a successful one.

Lohezet casts one of the following spells, requiring no material components and using Intelligence as the spellcasting ability (spell save DC 17):

At will: detect magic, light, prestidigitation

2 each/day: dimension door, mage armor

1 each/day: arcane eye, dominate person, wall of force