Dormammu of Legend

Warworld was an incomparably terrifying war fortress. It was a golden metal planet, its entire surface packed with all kinds of high-tech weapons that could be transformed into terrifying instruments of destruction at any moment. Its ruler, Mongu, was a notorious invader in the universe. What he loved most was piloting Warworld to conquer planet after planet, slaughter civilians, and then enslave powerful warriors to fight for him. The inside of Warworld was a gigantic arena.