Lich

An undead spellcaster who has achieved eternal existence by confining his or her life essence in a magical receptacle called a phylactery. They cannot be destroyed permanently unless this receptacle is destroyed, so they are always well-hidden and powerfully defended. Otherwise, the lich will reform at full power 10 days later.

Liches are always powerful and almost always evil, often using their unending existences to devise and enact fiendish plots. Particularly old and powerful liches are called archliches. The Lich Queen Faerlak was the greatest of these, achieving, briefly, demi-godhood.