Azrael

Revived Nature. Azrael's connection to death gives him several benefits. Azrael has advantage on saving throws against disease and being poisoned. He also does not need to eat, drink, breathe, or sleep.

Limited Magic Immunity. Azrael can't be affected or detected by spells of 5th level or lower unless he wishes to be. He has advantage on saving throws against all other spells and magical effects.

Regenerate. Azrael may channel the life force of others to heal his wounds.  On the start of Azrael's turn, each creature within 30ft of him takes 1 necrotic damage. Azrael regains hit points equal to the amount of damage dealt. If Azrael regains at least 1 hit point, any severed limbs Azrael has lost will rapidly grow back as if under the effect of regenerate. 

Ethereal Jaunt. Like a ghost, Azrael has the ability to slip in and out of the Ethereal Plane. As a bonus action, Azrael can teleport to an unoccupied space he can see within 30 feet of himself.

Innate Spellcasting. Azrael's innate spellcasting ability is Charisma (spell save DC 21, +14 to hit with spell attacks). Azrael can innately cast the following spells, requiring no material components:

At will: detect thoughts, disguise self, minor illusion, steel wind strike

3/day each: absorb elements, charm person, invisibility, modify memory, scatter

1/day each: dominate person, true seeing, feign death, dream, wind walk

Multiattack. Azrael makes four attacks: two with his cursed blade and two with his daggers.

Cursed Blade (Katana). Melee Weapon Attack: +14 to hit, reach 5 ft., one target. Hit: 31 (4d10 + 8) slashing damage and the target is cursed if it is a creature. The magical curse takes effect whenever the target takes a short or long rest, filling the target's thoughts with horrible images and dreams. The cursed target gains no benefit from finishing a short or long rest. The curse lasts until it is lifted by a remove curse spell or similar magic.

Poison Dagger. Ranged Weapon Attack: +14 to hit, range 20/60 ft., one target. Hit: 13 (2d4 + 8) piercing damage. The target must succeed on a DC 21 Constitution saving throw or become poisoned. While poisoned in this way, the target can't regain hit points, and it takes 21 (6d6) poison damage at the start of each of its turns. The poisoned target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If the poisoned target drops to 0 hit points, it stabilizes. 

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

Thrown Dagger. Azrael makes an attack with his poison dagger.

Teleport. Azrael uses his Ethereal Jaunt.

Psychic Drain (Costs 2 Actions).  Azrael targets one creature cursed by his Cursed Blade. The target takes 12 (3d6) psychic damage, and Azrael regains hit points equal to the damage the creature takes. Azrael can drain an additional  4 (1d6) for each additional hit landed with his cursed blade against that creature.