Magneto is the primary antagonist in most X-Men continuities mainly the first season of X-Men Evolution, the film X-Men and its second sequel. He is a mutant and is a longtime friend of Professor Charles Xavier, the founder of the X-Men. Magneto's view on mutants is that they should punish humans for mistreating them, as opposed to Xavier's view, which is that they should remain peaceful and in time will gradually become accepted. Despite being enemies due to their opposing views, Xavier and Magneto still maintain their close friendship as well as possible.
In some continuities, Magneto, as well as the rest of the Brotherhood, join forces with the X-Men to fight the common enemy.