Demonic Aura. At the start of each of the Abyssal Lich's turns, each creature within 10 feet of it must succeed on a DC 18 Constitution saving throw or take 14 (4d6) necrotic damage and have their hit point maximum reduced by an amount equal to the necrotic damage taken. This reduction lasts until the creature finishes a long rest. The creature dies if this effect reduces its hit point maximum to 0.

Magic Resistance. The Abyssal Lich has advantage on saving throws against spells and other magical effects.

Spellcasting. The Abyssal Lich is a 15th-level spellcaster. Its spellcasting ability is Intelligence (spell save DC 19, +11 to hit with spell attacks). It requires no material components to cast its spells. The Abyssal Lich has the following spells prepared:

• Cantrips (at will): Chill Touch, Mage Hand, Minor Illusion, Toll the Dead
• 1st level (4 slots): Shield, Magic Missile, Detect Magic
• 2nd level (3 slots): Mirror Image, Hold Person
• 3rd level (3 slots): Counterspell, Fireball, Dispel Magic
• 4th level (3 slots): Blight, Phantasmal Killer
• 5th level (3 slots): Cloudkill, Dominate Person
• 6th level (1 slot): Circle of Death
• 7th level (1 slot): Finger of Death
• 8th level (1 slot): Power Word Stun

Rejuvenation. If it has a phylactery, a destroyed Abyssal Lich gains a new body in 1d10 days, regaining all its hit points and becoming active again. The new body appears within 5 feet of the phylactery.

Actions

Multiattack. The Abyssal Lich makes two attacks with its Abyssal Morning Star or casts one spell.

Abyssal Morning Star. Melee Weapon Attack: +10 to hit, reach 5 ft., one target. Hit: 21 (4d6 + 7) bludgeoning damage plus 10 (3d6) necrotic damage. If the target is a creature, it must succeed on a DC 18 Wisdom saving throw or become frightened until the end of the Abyssal Lich's next turn.

Necrotic Bolt. Ranged Spell Attack: +11 to hit, range 120 ft., one target. Hit: 27 (6d8) necrotic damage.

Paralyzing Gaze (Recharge 5-6). The Abyssal Lich targets one creature it can see within 30 feet. The target must succeed on a DC 19 Constitution saving throw or be paralyzed for 1 minute. The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

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

Legendary Actions (3/Turn) The Abyssal Lich 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 Abyssal Lich regains spent legendary actions at the start of its turn.

• Cantrip. The Abyssal Lich casts a cantrip.
• Abyssal Strike. The Abyssal Lich makes one attack with its Abyssal Morning Star.
• Teleport (Costs 2 Actions). The Abyssal Lich magically teleports up to 60 feet to an unoccupied space it can see.
• Shadow Eruption (Costs 3 Actions). The Abyssal Lich causes shadows to erupt in a 20-foot radius around it. Each creature in that area must succeed on a DC 18 Dexterity saving throw or take 21 (6d6) necrotic damage and be pushed 10 feet away from the Abyssal Lich.