Age of Apocalypse

Legion (David Haller), a powerful psionic mutant on Earth and son of Professor Charles Xavier and Gabrielle Haller, travels back in time with the intention of killing Magneto,Xavier's former best friend and current archnemesis, to improve conditions. When David is on the verge of ending Magneto's life, Xavier places himself between the two, and Legion inadvertently kills Xavier instead. Due to a "Grandfather paradox", Legion then ceases to exist as Xavier now died before Legion was even fathered.

Because of Xavier's sacrifice, Magneto comes to believe in his late friend's dream of peaceful coexistence between humans and mutants. Apocalypse, an immortal mutant who has been alive for centuries, was monitoring the fight. In this reality, he chooses this moment as the perfect time to begin his "survival of the fittest" genetic war, which doesn't happen in the regular Marvel Universe until ten years later.

In this timeline, Magneto assembles the X-Men before Apocalypse establishes himself as a major power. Apocalypse comes to rule all of North America (the Statue of Liberty is replaced by a gigantic statue of his visage), and initiates a worldwide genocidal campaign of "cullings" in which millions of humans die. The few that survive live in parts of Europe and Africa which were not devastated by nuclear weapons. Fleets of Sentinels are their only defense.

Meanwhile, the disturbance of the time line leads to a crystallization wave of the M'Kraan Crystal that is heading toward Earth.

Magneto, as leader of the X-Men, leads a resistance movement against Apocalypse's forces. Early in the timeline, his daughter the Scarlet Witch is killed by one of Apocalypse's henchmen, Nemesis (later Holocaust ). Later, Weapon X (Wolverine) and Jean Grey leave the X-Men to follow their own separate path. The true beginning of the Age of Apocalypse, however, is in the comic book X-Men Alpha.

There are alot of comics published that are related to this comic. Most of it telling the parts of each individual who try in challenging Apocalypse or stopping his men and lackeys. All in all this is a great comic to read and be sure to start at the beginning of this series.