Baba Yaga

 Legendary Resistance (3/Day): If Baba Yaga fails a saving throw, she can choose to succeed instead.

Innate Spellcasting: Baba Yaga’s spellcasting ability is Intelligence (spell save DC 27, +19 to hit with spell attacks). She can innately cast the following spells, requiring no material components:

At will: Detect Magic, Invisibility, Misty Step, Shield, Telekinesis
3/day each: Counterspell, Dispel Magic, Globe of Invulnerability, Power Word Stun, Shapechange
1/day each: Foresight, Imprisonment, Power Word Kill, True Resurrection

Master of Hexes: Baba Yaga can cast hex spells (e.g., Bestow Curse, Hex) without expending spell slots.

Dark Bargain: Baba Yaga can make a dark bargain with a willing creature. The bargain grants the creature a boon (such as +2 to an ability score or proficiency in a skill) at the cost of a curse (such as vulnerability to a damage type or disadvantage on certain saving throws). Only one bargain can be active on a creature at a time.

 Multiattack: Baba Yaga makes four attacks with her magic staff or casts a spell and makes two attacks with her staff.

Magic Staff: Melee Weapon Attack: +14 to hit, reach 5 ft., one target. Hit: 19 (3d8 + 6) bludgeoning damage plus 22 (5d8) necrotic damage.

Eldritch Blast: Ranged Spell Attack: +19 to hit, range 120 ft., one target. Hit: 18 (4d8) force damage.

Soul Drain (Recharge 5-6): Baba Yaga targets one creature she can see within 60 feet. The target must succeed on a DC 27 Constitution saving throw or take 90 (20d8) necrotic damage. Baba Yaga regains hit points equal to half the damage dealt.

Hexing Glare: Baba Yaga can use a bonus action to glare at a creature she can see within 60 feet. The target must succeed on a DC 27 Wisdom saving throw or be cursed until the end of Baba Yaga’s next turn. The curse imposes disadvantage on all attack rolls and saving throws.

Witch’s Cackle: When a creature within 30 feet of Baba Yaga fails a saving throw, she can use her reaction to cackle and impose disadvantage on the creature’s next saving throw.

Baba Yaga 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. Baba Yaga regains spent legendary actions at the start of her turn.

Cast a Spell: Baba Yaga casts a spell of 3rd level or lower.

Magic Staff Attack: Baba Yaga makes one attack with her magic staff.

Cloak of Shadows (Costs 2 Actions): Baba Yaga becomes invisible until the start of her next turn or until she attacks or casts a spell.