Legion, a powerful psionic mutant on Earth and son of Professor Charles Xavier, travels back in time with the intention of killing Magneto. He believes Magneto's death will allow Xavier to achieve his dream of human/mutant equality. However, Legion traveled to a time when Magneto and Xavier were still friends, Xavier dies trying to protect Magneto, Legion vanishes, and a new time-line is created.
Wolverine: Weapon X was a loner and, initially, an unwilling recruit to the X-Men. He reconsidered after meeting the team's telepath, Jean Grey. The Two had an instant connection and eventually became lovers. Logan trained Mageneto's newer recruits including Kitty Pryde.
Jean Grey: Jean Grey was the first mutant, other than Magneto's own children, recruited to be an X-Man. Jean's parents knew something was wrong with their daughter and, with no place else to turn, contacted Magneto. Magneto, who had recently announced his intentions to train mutants in the use of their powers, arrived and took Jean into his care.
Apocalypse: Apocalypse, a strict believer in the survival of the fittest, launched an offensive against humankind. With Xavier dead, and Apocalypse beginning his offensive ten years earlier than he did in the Marvel Universe, there was no one to stand in his way.
Dark Beast: Henry McCoy was one of Apocalypse's leading scientists. He worked on expanding genetic mutation with his mentor, Nathan Essex, AKA Sinister. McCoy was responsible for creating the process needed to build the gene spliced infinite army used to take over the world during the Age of Apocalypse.