Corvus the terrifying

Innate Spellcasting. The Corvus' innate spellcasting ability is Charisma (spell save DC 18, +10 to hit with spell attacks). He can innately cast the following spells, requiring no material components:

At will: levitate, invisibility

Cantrips (at will): eldritch blast, chill touch, booming blade, vicious mockery

1st level (0 slots): arms of hadar, hellish rebuke, hex

2nd level (0 slots): hold person, darkness 

3rd level (0 slots): counterspell, enemies abound, fear, spirit shroud

4th level (0 slots): raulothim's psychic lance, sickening radiance, banishment*

5th level (4 slots): synaptic static, scrying, wall of force

6th level (1 slot): eyebite

7th level (1 slot): power word pain

8th level (1 slot): maddening darkness

Legendary Resistance (3/Day). If the Corvus fails a saving throw, he can choose to succeed instead.

Invocations:  Agonizing Blast, Ascendent Step, Devil's Sight, Eldritch Mind, Repelling Blast, Shroud of Shadow, Witch's Sight

Fey Prescence, Misty Escape, Beguiling Defense, Dark Delirium

Iron Beak. Melee Weapon Attack: +10 to hit, reach 5 ft.  one target. Hit:  12(1d6 + 8) piercing damage.

Transfer essence (Recharge 5–6). Transfer essence to different puppet. Current puppet is destroyed

Corvus 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 Corvus regains spent legendary actions at the start of its turn.

Cast Cantrip. Cast a cantrip

Activate Ability. Activate a current spell or use invocation spell

Cast Spell (Costs 2 Actions). Can use a level 5 spell slot or higher