In December 2004, Twentieth Century Fox hired screenwriter Sheldon Turner to draft a spin-off X-Men film, and he chose to write Magneto, pitching it as "The Pianist meets X-Men." In April 2007, David S. Goyer was hired to direct. Turner said the script was set from 1939 to 1955, and that it follows Magneto trying to survive in Auschwitz. He meets Xavier, a soldier, during the liberation of the camp. He hunts down the Nazi war criminals that tortured him in Europe and Argentina, and his lust for vengeance turns him and Xavier into enemies.

In May 2006, Ian McKellen said he would reprise the role using the computer-generated facelift applied to him in the prologue of X-Men: The Last Stand. Lauren Shuler Donner stated that the film would need McKellen to anchor the story, which would take place in flashbacks. With Goyer's hiring in 2007, it was said actors in their twenties would play the characters. Avi Arad said the film is planned for a 2009 release, and like Wolverine, it may be shot in Australia.