There are fewer beings on Earth more powerful than Magneto. The Master of Magnetism, Magneto is capable of levitation, energy projection, force field construction, and the total mastery of metal manipulation. It is with these skills and his desire to turn the Earth into a paradise for mutants – at the cost of the lesser Homo sapiens – that Magneto exists as the X-Men’s arch-nemesis. But there was once a period when Magneto attempted to turn a new leaf and prove to the world that he could put his violent past behind him. The purest of intentions always come with a caveat, however, and despite his promises, Magneto created a weapon so powerful that he could have brought the entire world to its knees with nothing more than a thought.
Source:https://www.cbr.com/xmen-magneto-conquers-earth-marvel-comics/