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

Fiendish Aura. Creatures within 20 feet of the Lich Lord must make a DC 20 Wisdom saving throw at the start of their turn or be frightened until the start of their next turn. While frightened, they also take 3d6 psychic damage.

Abyssal Regeneration. The Lich Lord regains 20 hit points at the start of each of his turns unless he is in direct sunlight or has been hit by radiant damage during the previous round.

Abyssal Wings. The Lich Lord's twisted wings allow him to hover above the battlefield. If he moves at least 20 feet before attacking, he deals an extra 3d10 necrotic damage on his next attack.

Multiattack. The Lich Lord makes three attacks, one with his Abyssal Claw, one with his Molten Tail, and one with a Hellfire Blast.

Abyssal Claw. Melee Weapon Attack: +14 to hit, reach 10 ft., one target. Hit: 22 (3d10 + 7) slashing damage + 14 (4d6) necrotic damage.

Molten Tail (Recharge 5–6). Melee Weapon Attack: +14 to hit, reach 15 ft., one target. Hit: 24 (3d12 + 7) bludgeoning damage + 10 (3d6) fire damage. The target must succeed on a DC 20 Strength saving throw or be knocked prone.

Hellfire Blast. Ranged Spell Attack: +15 to hit, range 120 ft., one target.
Hit: 35 (6d10) fire damage + 24 (4d12) necrotic damage. If the target is reduced to 0 hit points, they are disintegrated into ash, and the Lich Lord gains temporary hit points equal to the fire damage dealt.

Soul Siphon (Recharge 5–6). The Lich Lord chooses one creature within 60 feet. The target must make a DC 20 Constitution saving throw. On a failed save, the target takes 60 (10d10) necrotic damage, and the Lich Lord regains hit points equal to half the damage dealt. On a successful save, the target takes half damage, and the Lich Lord gains no healing.

The Lich Lord can take 3 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. The Lich Lord regains spent legendary actions at the start of his turn.

Abyssal Wing Flare (Cost: 1 Action). The Lich Lord beats his wings, releasing a shockwave of molten energy. Each creature within 15 feet of him must succeed on a DC 20 Dexterity saving throw or take 18 (4d8) fire damage and be knocked back 15 feet.

Hellfire Ray (Cost: 2 Actions). The Lich Lord fires a beam of hellfire at a target within 120 feet. The target must make a DC 20 Dexterity saving throw, taking 32 (5d10) fire damage on a failed save, or half as much on a successful one.

Demonic Ascension (Cost: 3 Actions). The Lich Lord becomes incorporeal until the start of his next turn, gaining immunity to all nonmagical damage and resistance to all magical damage.

When the Lich Lord reaches half health, the battlefield becomes even more dangerous. Lava erupts unpredictably, and Abyssal energy fills the air.

Abyssal Catastrophe (Recharge 6): The Lich Lord releases a massive wave of necrotic energy, forcing all creatures within 60 feet to make a DC 20 Constitution saving throw or take 80 (10d12) necrotic damage and be knocked prone.