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

Undying. If Zalazar is slain, his soul refuses to accept its fate and lives on as a disembodied spirit that fashions a new body for itself after 10 days. Zalazar's soul can fashion a new body even if its old body was burned to ash or otherwise obliterated as long as its Phylactery remains intact.

Unusual Nature. Zalazar doesn’t require air, food, drink, or sleep.

Robe of Eyes. Zalazar wears a Robe of eyes that cannot be closed or averted, The robe lets Zalazar see in all directions, and gives him advantage on Wisdom (Perception) checks that rely on sight. It also gives Zalazar Truesight.

Illusionists Bracers. Zalazar uses Rotten Fate, Eye of Vecna or Spellcasting. He may then cast two cantrips.

Rotten Fate. Zalazar causes necrotic magic to engulf one creature he can see within 120 feet of himself. The target must make a DC 22 Constitution saving throw, taking 96 (8d8 + 60) necrotic damage on a failed save, or half as much damage on a successful one. A Humanoid killed by this magic rises as a zombie at the start of Zalazar's next turn and acts immediately after Zalazar in the initiative order. The zombie is under Zalazar's control.

Eye of Vecna. Zalazar channels the eye of Vecna imbedded in his Phylactery to either use an action to see as if he were wearing a ring of X-ray vision, or cast eyebite.

Spellcasting. Zalazar is a 20th level caster and casts one of the following spells, requiring no material components and using Intelligence as the spellcasting ability (spell save DC 23):

Cantrips: Fire bolt, Chill Touch, Toll the Dead, Sapping Sting, True strike

At will: animate dead (as an action), detect magic, dispel magic, fly, lightning bolt, mage hand, prestidigitation, Fog Cloud, Create Undead

3/day each: dimension door, Scrying](as an action), invisibility

2/day each: Soul Cage, Bigby's Hand , Finger of Death

1/day each: dominate monster, globe of invulnerability, plane shift (self only)

1/day: Blade of Disaster

Vile Teleport. Zalazar teleports, along with any equipment he is wearing or carrying, up to 30 feet to an unoccupied space he can see. He can cause each creature of his choice within 15 feet of his destination space to take 10 (3d6) psychic damage. If at least one creature takes this damage, Zalazar regains 80 hit points.

Zalazar can take up to two reactions per round but only one per turn.

Dread Counterspell. Zalazar utters a dread word to interrupt a creature he can see that is casting a spell. If the spell is 4th level or lower, it fails and has no effect. If the spell is 5th level or higher, Zalazar makes an Intelligence check (DC 10 + the spell’s level). On a success, the spell fails and has no effect. Whatever the spell’s level, the caster takes 10 (3d6) psychic damage if the spell fails.

Fell Rebuke. In response to being hit by an attack, Zalazar utters a fell word, dealing 10 (3d6) necrotic damage to the attacker, and Zalazar teleports, along with any equipment he is wearing or carrying, up to 30 feet to an unoccupied space he can see.