For the 80's incarnation look here. Mumm-Ra, is the main antagonist of the new ThunderCats. An ancient and immortal evil, Mumm-Ra is a powerful sorcerer with a vast army of minions. He seeks the same ancient artifacts as the ThunderCats and will destroy anyone and anything that stands in his way. He is based on the 1980s character of the same name. He is voiced by Robin Atkin Downes.