Mumm-Ra

Priest to the Egyptian Pharos, learned Black Magic
Asked the Ancient Spirits of Evil for more power
They granted his request, turning him into the undead
Tried to overthrow the Pharaoh but failed, imprisoned in a tomb for 600 years;
Forced to build 4 statues in Spirits of Evil’s likeness before they would free him;
Transformed into a more powerful version of himself when invoking their power
Sought to obtain the Eye of Thundera, a source of unlimited power
Assume different forms to deceive the ThunderCats on various occasions
Employed the mutants & the Lunataks to do his bidding
Seeing his own reflection would force him to revert to his mummified form