Avatar of Orcus

Innate Spellcasting. The Avatar of Orcus’s spellcasting ability is Charisma (spell save DC 18, +10 to hit with spell attacks). It can innately cast the following spells:

At will: chill touch (11th level)
3/day: blight

Legendary Resistance (3/Day). If the Avatar of Orcus fails a saving throw, it can choose to succeed instead.

Magic Weapons. The Avatar of Orcus's weapon attacks are magical.

Multiattack. The Avatar of Orcus makes two attacks with its greataxe.

Greataxe. Melee Weapon Attack: +11 to hit, reach 5 ft., one target. Hit: 13 (1d12 + 6) slashing damage plus 7 (2d6) necrotic damage.

Tail. Melee Weapon Attack: +11 to hit, reach 5 ft., one target. Hit: 15 (2d8 + 6) piercing damage plus 5 (1d8) poison damage.

The Avatar of Orcus 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. The Avatar of Orcus regains spent legendary actions at the start of its turn.

Tail. The Avatar of Orcus makes one tail attack.

A Taste of Undeath. The Avatar of Orcus casts chill touch (11th level).

Necrotic Blast (Costs 2 Actions). A sphere of negative energy blasts out in a 30-foot-radius sphere from the Avatar of Orcus. Each creature in that area must make a DC 18 Constitution saving throw. A target takes 28 (8d6) necrotic damage on a failed save, or half as much damage on a successful one.