Xyvon, Prophet of the Green Blood

Blood of the Green (Passive). At the start of each of Xyvon’s turns, he regains 10 hit points unless he has taken radiant or fire damage since the end of his last turn.

Corruptive Blood. When hit by a melee weapon attack, the attacker must succeed on a DC 16 Constitution saving throw or take 1d8 necrotic damage and become poisoned until the end of their next turn. If they are already poisoned, they also become incapacitated until the end of that turn (once per creature).

Multiattack. Xyvon makes two melee attacks and casts one spell (cantrip or spell with casting time 1 action).

Spellcasting. Xyvon is a 10th-level spellcaster. His spellcasting ability is Charisma (spell save DC 16, +8 to hit). He has the following spells prepared:

Cantrips (at will): Chill Touch, Thaumaturgy, Minor Illusion
1st level (4): Mage Armor, Command, shield, Inflict Wounds
2nd level (3): Mirror Image, Hold Person, Suggestion
3rd level (3): Counterspell, Vampiric Touch, Fear
4th level (2): Greater Invisibility, Phantasmal Killer
5th level (1): Cloudkill (appears as a swirling toxic green miasma)

Pestilent Touch. Melee Spell Attack: +9 to hit, reach 5 ft., one creature. Hit: 2d10 necrotic + 1d8 poison damage.

Explosion of Green Blood (1/turn, up to 3/day). Creatures within 15 ft. of Xyvon must succeed on a DC 16 Constitution saving throw or take 4d6 poison damage and suffer disadvantage on attack rolls and saving throws against Xyvon until the end of their next turn.