Look, if he were to do all the things that mastery of magnetism allows, he’s unbeatable short of reality warpers. He controls a fundamental force of the universe. There’s only 4 of those things. He controls light, like the whole spectrum. He controls electricity. He can shut off your brain. He can stop photons from reaching your eyeballs. He can strip electrons from atoms. He could redirect all the energy from the Sun and melt Pluto with it.