Red Skull
During the "AXIS" storyline, Magneto finds out that the Red Skull has turned Genosha into a concentration camp for mutants and still has Professor X's brain inside him. Magneto attacks the Red Skull, but is quickly stopped by the S-Men. The Red Skull mind-tortures Magneto with visions of those closest to the mutant suffering while being unable to do anything to stop it. After being freed by the Scarlet Witch, Rogue and Havok, he bites down on a vial beneath his skin of Mutant Growth Hormone, giving himself enough power to fight. When the Scarlet Witch, Rogue and Havok want to leave the island and alert the rest of the Avengers and the X-Men of what the Red Skull is doing, Magneto wants to stay and fight. Before they can do anything, the Red Skull appears. The Red Skull now has the group mind-controlled. He plans on using the Scarlet Witch's power to shape reality in his image. He tells Magneto to bow if the Scarlet Witch were to remain alive, but Magneto performs a sneak attack enough to break the Red Skull's control over the others. After killing the S-Men, Magneto attacks the Red Skull, who then tells Magneto that Professor X's greatest fear was leading the X-Men. Magneto kills the Red Skull while the others look on in horror. Magneto believes everything is over, only for the Red Skull to appear as a giant called "Red Onslaught".