The series is a modernized re-imagining of Marvel's long-running X-Men comic book franchise as part of its Ultimate Marvel universe following the adventures of the Ultimate X-Men as they fight the evil terrorist group known to the world as the Brotherhood and anti-mutant organizations. After the devastating events of Ultimatum event. The series ended with issue 100 and it was somewhat continued in the Ultimatum: X-Men Requiem one-shot and the Ultimate Comics X series, which follows a new team of mutants and the remains of the Ultimate X-Men.
Ultimate X-Men series:
Ultimate X-Men (2001)
Ultimate Comics X (2011)
Ultimate Comics: X-Men (2011)
Cataclysm: Ultimate X-Men (2013)