Mumm-Ra: The Everliving
Age: Older than dirt, by at least a thousand years.
Sex: Male
Species/Race: Egyptian Mummified Corpse
Alliance: Bad Guys

Appearance: See Picture

Weapons/Skills/Powers: He is the ThunderCats' arch enemy on Third Earth. Mumm-ra resides in the Black Pyramid and longs to possess the power within the Eye of Thundera. He's a pretty powerful master of dark magic. He can change from his weakling mummy form into a buff force of evil, but he must re-energize himself within his sarcophagus after doing so. The Ancient Spirits of Evil so graciously grant his powers and everlasting life.

Obviously, his magic and evil, scheming mind are his best weapons.

Background: As I see it, Mumm-Ra was a living being long ago at a time when Third Earth was known as First Earth. I figure, he lived his life as a pretty decent Egyptian Pharoah. Basically, because of a greedy, double-crossing rival, he was possessed by the Ancient Spirits of Evil.
Now, Mumm-Ra is beholden to the will of the ASOE, his poor decrepit body and possessed spirit unable to deny the power which granted him everlasting life.