True Believers: What If Legion Had Killed Magneto? #1

Synopsis

Legion succeeds in killing Magneto in the past (thus negating his own existence as Maggie once saved his mother's life before he was born). Without the polarizing threat of Magneto to make the X-Men strong, they become little more than pro-mutant media figures. Thus, when Apocalypse and his forces attack, the X-Men are ill equipped to deal with the threat. Scott and Jean come out of retirement to join the fight but Jean ends up killing 100,000 people with the Phoenix force. As a result, the world now hates and fears mutants and Scott opens X-Mansion as a school to help repair the rift.