Lich Attributes

Saving Throws: Con +10, Int +12, Wis +9
Skills: Arcana +18, History +12, Insight +9, Perception +9
Damage Resistance: Cold, Lightning, Necrotic
Damage Immunities: Poison, Bludgeoning, Piercing, and Slashing From Nonmagical Attacks
Condition Immunities: Charmed, Exhaustion, Frightened, Paralyzed, Poisoned
Senses: Truesight 24m, passive Perception 19
Languages: Common Plus Up To Five Other Languages
Challenge: 21 (33,000 XP)

Legendary Resistance (3/Day).: If the lich fails a saving throw, it can choose to succeed instead.
Rejuvenation.: If it has a phylactery, a destroyed lich gains a new body in 1d10 days, regaining all its hit points and becoming active again. The new body appears within 1m of the phylactery.
Spellcasting.: The lich is an 18th-level spellcaster. Its spellcasting ability is Intelligence (spell save DC 20, +12 to hit with spell attacks). The lich has the following wizard spells prepared:

Cantrips (at will): Mage Hand, Prestidigitation, Ray of Frost
1st level (4 slots): Detect Magic, Magic Missile, Shield, Thunderwave
2nd level (3 slots): Detect Thoughts, Invisibility, acid arrow, Mirror Image
3rd level (3 slots): Animate Dead, Counterspell, Dispel Magic, Fireball
4th level (3 slots): Blight, Dimension Door
5th level (3 slots): cloudkill, Scrying
6th level (1 slot): disintegrate, globe of invulnerability
7th level (1 slot): finger of death, Plane Shift
8th level (1 slot): dominate monster, Power Word Stun
9th level (1 slot): power word kill
Turn Resistance.: The lich has advantage on saving throws against any effect that turns undead.

Paralyzing Touch.: Melee Spell Attack: +12 to hit, reach 1m, one creature. Hit: (3d6) cold damage. The target must succeed on a DC 18 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

Description: Lich 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. Lich regains spent legendary actions at the start of their turn.
Cantrip.: The lich casts a cantrip.
Paralyzing Touch (Costs 2 Actions).: The lich uses its Paralyzing Touch.
Frightening Gaze (Costs 2 Actions).: The lich fixes its gaze on one creature it can see within 2m of it. The target must succeed on a DC 18 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 lich's gaze for the next 24 hours.
Disrupt Life (Costs 3 Actions).: Each non-undead creature within 4m of the lich must make a DC 18 Constitution saving throw against this magic, taking 21 (6d6) necrotic damage on a failed save, or half as much damage on a successful one.

Lich