Medium undead, chaotic evil
Armor Class 21 (natural armor)
Hit Points 285 (30d8 + 150)
Speed 30 ft.
Saving Throws Con +12, Int +17, Wis +12
Skills Arcana +24, History +24, Insight +12, Perception +12, Religion +17
Damage Resistances cold, lightning
Damage Immunities necrotic, poison; bludgeoning, piercing, and slashing from nonmagical attacks
Condition Immunities charmed, exhaustion, frightened, paralyzed, poisoned
Senses truesight 120 ft., passive Perception 22
Languages Common plus up to seven other languages
Challenge 23 (50,000 XP)
Special Equipment. Vecna wields the Hand and Eye of Vecna. He does not suffer the detrimental properties of those artifacts.
Legendary Resistance (3/Day). If the archlich fails a saving throw, it can choose to succeed instead.
Magic Resistance. Vecna has advantage on saving throws against spells and other magical effects.
Premonition. Vecna cannot be surprised.
Preparation. When preparing his spells, Vecna can swap out any spell on his list of prepared spells for another wizard spell of the same level.
Regeneration. At the start of his turn, Vecna regains 10 hit points.
Rejuvenation. If it has a phylactery, a destroyed archlich 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.
Spellcasting. The archlich is a 20th-level spellcaster. Its spellcasting ability is Intelligence (spell save DC 25, +15 to hit with spell attacks). The lich has the following wizard spells prepared:
Cantrips (at will): mage hand, ray of frost, shocking grasp
1st level (at will): detect magic, magic missile, shield
2nd level (at will): arcane lock, detect thoughts, invisibility, mirror image
3rd level (at will): animate dead, counterspell, dispel magic, fireball
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): forcecage, finger of death, teleport
8th level (2 slots): feeblemind, maze
9th level (2 slots): meteor swarm, time stop
Turn Resistance. The archlich has advantage on saving throws against any effect that turns undead.
Paralyzing Touch. Melee Spell Attack: +17 to hit, reach 5 ft., one creature. Hit: 21 (6d6) cold damage. The target must succeed on a DC 20 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.
The archlich can take 3 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. The archlich regains spent legendary actions at the start of its turn.
At-will spell. The archlich casts one of its at-will spells.
Paralyzing Touch. The archlich uses its Paralyzing Touch.
Frightening Gaze (Costs 2 Actions). The archlich fixes its gaze on one creature it can see within 10 feet of it. The target must succeed on a DC 20 Wisdom saving throw against this magic or become frightened for 1 minute. The frightened target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a target's saving throw is successful or the effect ends for it, the target is immune to the archlich's gaze for the next 24 hours.
Disrupt Life (Costs 3 Actions). Each non-undead creature within 20 feet of the archlich must make a DC 20 Constitution saving throw against this magic, taking 42 (12d6) necrotic damage on a failed save, or half as much damage on a successful one.