Ultimate War #1 (2002)

Ultimates vs Ultimate X-Men
Following the events of "Ultimate X-Men #25," Magneto is free, and has retaken control of the Brotherhood of Mutants to continue moving his agenda forward. The Ultimates are called up by the government to deal with the threat, and though they have some success on that front, they're not too pleased with what they find when they go to the X-Men for reinforcements.
Release Date: 2002