A monster in
Dungeons and Dragons.
While a Demilich sounds like something that is a lesser form of a
Lich, it is actually much more powerful.
A Demilich has been
undead so long that most of his essence has transferred to the
Negative Energy Plane,
transcending his physical form. He is immune to most normal attacks and is capable of
killing a person in many ways, including
sucking out his soul.