Don't let his withered body fool you, he's extremely powerful and has myraid tricks up his bandaged sleeves. He uses all sorts of dark magic to try to defeat the Thundercats. His most impressive feat is metamorphosis, although trapped in his emaciated form most of the time, he is able to call on the Spirits to transform him into the powerful Mumm-Ra the everliving. In this form, he is an extremely powerful warrior--but he grows weaker the longer he stays in it, and must return to his black Pyramid to renew his strength. His other weakness is his reflection.
The primary nemesis of the Thundercats, this slave to the Ancient Spirits of Evil has survived for thousands of years on Third Earth. He possesses incredible magical powers, and is also the wielder of the awesome Sword of Plundarr. His only weakness is a limited stamina; he needs often to return to his Pyramid to regenerate.