Ultimate War

Ultimate War is a comic book limited series produced by Marvel Comics featuring the Ultimates and the Ultimate X-Men. The series contains four books, released between December 8, 2002 and February 23, 2003. It was written by Scottish comics author Mark Millar with art by Chris Bachalo.
It is collected as part of the Ultimate X-Men series of trade paperbacks. This was the first time the Ultimates as a team had crossed over with characters from the Ultimate Marvel Universe.
Plot
Previously, the X-Men defeated Magneto and pronounced him dead. Rather than turning Magneto over to the authorities and virtually ensuring the death penalty for him, Professor X secretly brainwashed his old friend and tried to rehabilitate him. However, the Beast inadvertently leaked this plan to Magneto's Brotherhood, believing that he was chatting with an online girlfriend. The Brotherhood used this to entrap Beast and gained enough knowledge to free their leader....