This haunting horror held the hearts of Sora's friends hostage. Time and again, Sora fought it back, but with each hard-won victory, it would simply slough its form and depart to another world. Its broad arsenal of magic made it a formidable foe to face alone, but in the end no Heartless could match the strength of Sora's resolve.
~ The Lich's Journal entry.
The Lich is a minor antagonist in the Kingdom Hearts series, and a member of the Pureblood Heartless.
Kingdom Hearts III
The Lich was seen after Sora came back from the Final World, where it was collecting the hearts of Riku, Donald, Goofy, King Mickey, Kairi, Ventus and Aqua, one at a time. This led Sora to fight against it in the various worlds that he has visited until he went back to the Realm of Darkness. Young Xehanort mentioned the Lich to Sora, possibly indicating that it is an ancient form of Heartless and that Sora was dooming himself by following it.
Powers and Abilities
Elemental Magic: The Lich is able to use various elemental magic, such as Fire, Thunder and Water.
Clone Creation: The Lich is able to create clones of itself in combat. These clones will explode if attacked.
Teleportation: The Lich is able to travel to various worlds through the use of dark portals that it creates.
Summoning: The Lich is able to call forth other Heartless to aid it in battle.