Big M (Earth-5423)

Big M's History

According to Calvin's back-story on MNN.com while in his reality:

"Calvin Rankin, alias "The Mimic", alias "The Big M", was captured by a combined strike force of the Avengers and S.H.I.E.L.D. troops earlier today in Wichita, Kansas. The infamous leader of the terrorist organization Brotherhood of Mutants was unrepentant as he was hauled off to an undisclosed location for processing and interrogation. Rankin's criminal activities, both on his own and with his so-called "Brotherhood," are estimated to have claimed the lives of over ten thousand people, including former Brotherhood leader Erik Lehsherr (A.K.A. Magneto), noted mutant activist Charles Xavier, and every single young student at Xavier's Private School in upstate New York."

Calvin felt that his entire life was predestined to make him who he was. It wasn't until he met the Exiles' Mimic that he was able to take a hard look at himself and change his own future for the better. With this revelation, he was able to transform his Brotherhood of Mutants into the newest incarnation of the X-Men.