Demands of Nessus. At the start of each of his turns, Asmodeus can choose one ally he can see within 30 feet of himself. The chosen ally loses 10 hit points, and Asmodeus regains the same number of hit points. If Asmodeus is incapacitated, he makes no choice; instead, the closest ally within 30 feet is the chosen ally.

Fear Aura. Any creature hostile to Asmodeus that starts its turn within 20 feet of him must make a DC 27 Wisdom saving throw, unless Asmodeus is incapacitated. On a failed save, the creature is frightened until the start of its next turn. If a creature's saving throw is successful, the creature is immune to Asmodeus’ Fear Aura for the next 24 hours.

Hellish Weapons. Asmodeus’ weapon attacks are magical and deal an additional 55 (10d10) necrotic damage on a hit (included in the attack.

Limited Magic Immunity. Asmodeus is not effected by spells of 6th level or lower unless he wishes to be. He has advantage on saving throws against all other spells and other magical effects.

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

At will: alter self(can become medium when changing his appearance), blight, charm person, dominate monster, fireball, hellish rebuke (8th level), invisibility (self only), scorching ray, teleport, wall of fire, wall of ice

3/day each: power word kill, power word stun, symbol(death only)

1/day each: meteor swarm, true resurrection, wish

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

Regeneration. Asmodeus regains 30 hit points at the start of his turn. If he takes radiant damage, this trait doesn't function at the start of his next turn. Asmodeus dies only if he starts his turn with 0 hit points and doesn't regenerate.

Ruby Rod. Many of Asmodeus’ powers come from the Ruby Rod he holds. Without his Ruby Rod, his Demands of Nessus and Hellish Weapon traits do not function, and he cannot use his Rest action, use lair actions, or cast his innate 1/day spells. His Challenge Rating without his Ruby Rod is 29.

Spellcasting. Asmodeus is a 20th level spellcaster. His spellcasting ability is Wisdom (spell save DC 27, +19 to hit with spell attacks). Asmodeus has the following cleric spells prepared:

Cantrips (at will): guidance, light, mending, resistance, thaumaturgy

1st level (at will): cure wounds, detect evil and good, detect magic, inflict wounds, protection from evil and good, shield of faith

2nd level (3 slots): blindness/deafness, lesser restoration, hold person, silence, spiritual weapon

3rd level (3 slots): animate dead, dispel magic, magic circle, sending, speak with dead

4th level (3 slots): banishment, death ward, locate creature

5th level (3 slots): flame strike, geas, planar binding

6th level (2 slots): blade barrier, harm, heal

7th level (2 slots): fire storm, resurrection

8th level (1 slot): earthquake, holy aura

9th level (1 slot): gate

Multiattack. Asmodeus makes four melee weapon attacks.

Ruby Rod. Melee Weapon Attack: +22 to hit, reach 10 ft., one target. Hit: 22 (2d8 + 13) bludgeoning damage plus 55 (10d10) necrotic damage.

Dagger. Melee or Ranged Weapon Attack: +19 to hit, reach 10 ft. or range 20/60 ft., one target. Hit: 15 (2d4 + 10) piercing damage plus 55 (10d10) necrotic damage.

Rest (1/day). Asmodeus gains the benefits of a long rest.

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

Asmodeus can take 5 legendary actions, choosing from the options below. Only one legendary action can be used at a time and only at the end of another creature's turn. Asmodeus regains spent legendary actions at the start of his turn.

Attack. Asmodeus makes a melee weapon attack.

Teleport. Asmodeus uses his Teleport action.

Spell (Costs 1-5 Actions). Asmodeus casts a spell of 1st-5th level, spending 1 legendary action per level of the spell.