Asharderis, King of Demons

Discorperation. When Asharderis drops to 0 hit points or dies, his body is destroyed but his essence travels back to the Endless Abyss, and he is unable to take physical form for a time.

King of Demons. All fiends with a Challenge of 20 or lower make attack roles against Asharderis with disadvantage.

Legendary Resistance (4/Day). If Asharderis fails a saving throw, he can choose to succeed instead.

Limited Magic Immunity. Asharderis is immune to spells of 6th level or lower unless he wishes to be affected. He has advantage on saving throws against all other spells and magical effects.

Magic Weapons. Asharderis's weapon attacks are magical.

Regeneration. Asharderis regains 25 hit points at the start of his turn as long as he has at least 1 hit point remaining.

Spellcasting. Asharderis is a 20th-level spellcaster. His spellcasting ability is Intelligence (spell save DC 25, +17 to hit with spell attacks). Asharderis has the following wizard spells prepared:

Cantrips (at will): mage hand, ray of frost, shocking grasp

1st level (at will): burning hands, ray of sickness, shield

2nd level (at will): arcane lock, knock, scorching ray

3rd level (at will): animate dead, counterspell

4th level (3 slots): blight, ice storm, phantasmal killer

5th level (3 slots): cloudkill, hold monster, wall of force

6th level (3 slots): chain lightning, circle of death, disintegrate

7th level (3 slots): fire storm, plane shift, simulacrum

8th level (2 slots): feeblemind, incendiary cloud

9th level (2 slots): power word kill, wish

Multiattack. Asharderis makes two staff attacks and uses Frightful Word once.

Staff of the Endless Abyss. Melee Weapon Attack: +18 to hit, reach 10 ft., one target. Hit: 19 (3d6 + 9) bludgeoning damage plus 10 (3d6) psychic damage.

Deceptive Words. Asharderis targets one creature can see within 120 feet of him. The target must succeed on a DC 26 Charisma saving throw or become charmed by Asharderis for 1 minute. The charmed target can repeat the saving throw if Asharderis does any damage to it. A creature that succeeds on this saving throw is immune to Asharderis's Deceptive Words for 24 hours.

Frightful Word. Asharderis targets one creature he can see within 30 feet of him. The target must succeed on a DC 27 Wisdom saving throw or become frightened of him for 1 minute. While frightened in this way, the target must take the Dash action and move away from Asharderis by the safest available route on each of its turns, unless there is nowhere to move, in which case it needn’t take the Dash action. The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Hurl Flame. Ranged Spell Attack: +17 to hit, range 120 ft., one target. Hit: 35 (10d6) fire damage.

Teleport. Asharderis magically teleports, along with any equipment he is wearing or carrying, up to 120 feet to an unoccupied space he can see.

Asharderis can take 4 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. Asharderis regains spent legendary actions at the start of his turn.

Attack. Asharderis makes a Staff of the Endless Abyss attack.

Teleportation. Asharderis magically teleports, along with any equipment he is wearing or carrying, up to 120 feet to an unoccupied space he can see.

Will of the Staff (Costs 2 Actions). The Staff of the Endless Abyss emits magical, unholy energy. Each creature of Asharderis’ choice in a 20-foot radius must make a DC 25 Dexterity saving throw, taking 45 (10d8) acid, bludgeoning, cold, fire, force, lightning, necrotic, piercing, poison, psychic or slashing damage (his choice) on a failed save, or half as much damage on a successful one.

Hellfire (Costs 3 Actions). Asharderis casts Delayed Blast Fireball.