Legendary Resistance (5/Day). If Aamon fails a saving throw, he can choose to succeed instead.

Undying. If Aamon is slain, his soul refuses to accept its fate and lives on as a disembodied spirit that fashions a new body for itself after 1d100 years. Aamon soul can fashion a new body even if its old body was burned to ash or otherwise obliterated. When the new body is complete, Aamon regains all his hit points and becomes active again. Aamon new body appears anywhere within 100 miles of where Aamon was slain.

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

 Multiattack. Aamon makes four attacks with Arcane Blast.

Arcane BlastRanged Spell Attack: +18 to hit, range 120 ft., one target. Hit: 15 (1d10 + 10) fire damage.

Mind Mastery. Aamon targets one creature it can see within 60 feet of it. The target must succeed on a DC 18 Intelligence saving throw, or Aamon causes it to use its reaction either to make one weapon attack against another creature Aamon can see or to move up to 10 feet in a direction of Aamon.  can’t be charmed are immune to this effect.

Aamon is a 20th-level spellcaster. His spellcasting ability is Intelligence (spell save DC 22, +14 to hit with spell attacks). He can cast disguise self and invisibility at will. He can cast fly and lightning bolt once each without expending a spell slot, but can’t do so again until he finishes a short or long rest. Aamon has the following wizard spells prepared:

Cantrips (at will): dancing lights, fire bolt, light, mage hand, prestidigitation

1st level (4 slots): mage armor, magic missile, shield, silent image

2nd level (3 slots): arcane lock, cloud of daggers, darkvision, knock

3rd level (3 slots): counterspell, dispel magic, fireball

4th level (3 slots): confusion, hallucinatory terrain, polymorph

5th level (3 slots): Bigby’s hand, geas, wall of force

6th level (2 slots): chain lightning, globe of invulnerability, Disintegrate 

7th level (2 slots): finger of death, symbol, teleport

8th level (1 slot): maze, mind blank

9th level (1 slot): meteor swarm, wish

Vile Teleport. Aamon 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, Aamon regains 80 hit points.

Aamon can take up to three reactions per round but only one per turn

.Dread Counterspell. Aamon 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, Aamon 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, Aamon utters a fell word, dealing 10 (3d6) necrotic damage to the attacker, and Aamon teleports, along with any equipment he is wearing or carrying, up to 30 feet to an unoccupied space he can see.