10 Mutants Who QUIT The X-Men
7. Bishop
Bishop was born in the 22nd century. His grandmother raised Bishop and his sister Shard in the mutant concentration camps of Brooklyn.
After the Summer Rebellion in which humans and mutants banded together to defeat the Sentinels, Bishop committed petty crimes to survive with his sister in the post-apocalyptic world. Bishop's grandmother regaled him with stories of the legendary X-Men, and he strove to live up to their example.
Bishop meets the X-Men when a mutant named Trevor Fitzroy escapes prison, through time, with ninety three other mutants. Bishop teams up with his idols, and they capture every single mutant.
Professor X offers Bishop a place on the team. Bishop is more than willing to join, declaring himself Xavier's bodyguard - a role he doesn't exactly excel at, as later a clone of Cable mortally wounds the professor.
During the Civil War: X-Men miniseries, Bishop sided against the X-Men with, none other than, a sentinel squad referred to as the O*N*E. This unlikely alliance happens after he gets into a row with Cyclops over his fears for the future.
However, in an attempt to arrest the X-Men, the O*N*E Sentinel Squad leader, General Demetrius Lezar, a rabid anti-mutant, orders Bishop to attack Cyclops. Bishop refuses and destroys a Sentinel instead.
Soon after, Bishop and Cyclops put their disagreement aside, and Bishop is back alongside the X-Men.