Weeell Sephy has supernova, an attack that destroys a few planets on its way to earth and would probably realistically destroy earth aswell. He also has heartless angel, which lowers HP to 1. He has slow and confuse, which I think would be particularly of use against superman. But then again he only has one arm.
He'd probably get speedblitzed if he can't cast slow or stop in time. But he has tons of HP.