DOMINO

When a chalk-white mercenary with a black-ringed eye joined Cable's team in 1991 and helped turn it into X-Force, nobody questioned her — not even Cable, her old comrade from their mercenary days. They should have. The woman was Vanessa Carlysle, the shapeshifter called Copycat, duplicated so completely — appearance, personality, fingerprints, even DNA — that the deception was undetectable. The real Domino, Neena Thurman, was at that moment a prisoner. She had been for over a year.

Copycat had been planted by the arms dealer who captured Neena: spy on Cable, and when ordered, bomb the team's headquarters. Instead, the impostor stalled — she had come to care for the teammates she was betraying. The truth surfaced only when Cable stormed his enemy's Italian stronghold and found the real Domino chained to a wall. Neena's first full appearance in the present day came on the last page of X-Force #11 (1992) — as a captive, more than a year after her double had debuted in her name.

Freed, Neena's first order of business was finding the woman who had eaten with her team, fought beside her friends and lived her life — with a gun, intending to kill her. She was talked into a deal instead, and the two women eventually reached an uneasy peace. But the record stands: for X-Force's entire first year, one of its founding members was a woman who appeared on no roster, and the luckiest mutant alive spent that year in a dungeon — the one outcome her probability power could not reach.