Thanatos is a villain from Chaos! comics. He first appeared in the 1999 Lady Death monthly series.
Thanatos was the only legitimate son of Lucifer, born by the mother Leviatha. Thanatos was spoiled by his mother, and generally grew up as a mediocre warrior, chemer, and administrator. After Leviatha was imprisoned by Lucifer, Thanatos was placed into lower positions and generally ignored by his father.
After The Trinity of Evil and their army of wraiths were fought off by the Archdukes of Hell , Thanatos was able to gain power in Hell. He was a mildly effective leader, but was totally overwhelmed when Lady Death returned to Hell from her battle with Genocide. Being a demon, Thanatos could not be killed by normal means, so Lady Death removed his head and kept it on a table. For some time Thanatps did nothing but give bad advice and attempt to make passes at Lady Death, but eventually Lucifer returned and gave him another body.
Thanatos attempted to fight Lady Death and the forces of Heaven on several other occasions, but never achieved any noteriety.