Creature type: You are considered an undead creature
Hit dice advancement: All of your hit dice below d8 become d8 instead. Reroll your hit point maximum using your new hit dice.
Ability score improvements: The lich gains +2 to its Constitution and Strength scores, and a +8 bonus which can be split among any of its mental ability scores (Intelligence, Wisdom, or Charisma). (For instance, you can give yourself +1 to Intelligence, +3 to Wisdom, and +4 to Charisma, or +5 to Intelligence, +1 to Wisdom, and +2 to Charisma.)
Natural armor: The lich gains a natural +4 bonus to AC. This does not count as wearing armor or wielding a shield.
Defenses: The lich gains resistance to cold, lightning, and necrotic damage, immunity to bludgeoning, piercing, and slashing damage from non-magical weapons and poison damage, and immunity to being charmed, exhausted, frightened, paralyzed, and poisoned.
True sight: The lich gains true sight for up to 120 feet, meaning that in this range it can see perfectly in normal and magical darkness, see invisible creatures and objects, automatically detect visual illusions and succeed on saving throws against them, and perceive the original form of a shapeshifter or a creature transformed by magic. The lich can also choose to see into the Ethereal Plane at this range (doing so requires no action).
Legendary resistance: The lich gains the legendary resistance trait: If it fails a saving throw, it can choose to succeed instead. This feature can be used three times per day.
Turn resistance: The lich gains turn resistance, giving it advantage on saving throws against any effect that turns undead.
Paralyzing grasp: The lich gains a paralyzing grasp attack. It is a melee spell attack (To hit: proficiency bonus + modifier of user’s spellcasting ability score; Reach: 5 ft.; Hit: 3d6 cold damage), and when hit, the target must make a Constitution saving throw (save DC: 8 + proficiency bonus + Constitution modifier) or become 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 successful save.
Rejuvenation: As a lich, you are not completely slain while your phylactery still exists. If you lose all your hit points, you no longer can make death saving throws, but your soul will regenerate 1d10 days after your death, your soul can seek out a suitable dead body, even if it is on another plane from where you were slain.