From Cassius Comics

Although secretly a reteaming of the five original X-Men, X-Factor was thought by the world as a group of humans who captured and detained dangerous mutants. The members of X-Factor eventually merged with the X-Men.

The members of the original X-Factor consisted of Angel/Archangel (Warren Worthington III), the Beast (Hank McCoy), Cyclops (Scott Summers), Iceman (Bobby Drake), Marvel Girl (Jean Grey) and Caliban.

The name later passed to a government-sponsored mutant team formed to act as a counterpart to the vigilante X-Men; This incarnation dissolved following Havok (Alex Summers)'s apparent death (he was in fact transported into the "Mutant X" dimension).

The members of that incarnation consisted of Havok, the Multiple Man (Jamie Madrox), Polaris (Lorna Dane), Quicksilver (Pietro Maximoff), Strong Guy (Guido Carosella), Wolfsbane (Rahne Sinclair), Valerie Cooper, Forge, Mystique (Raven Darkholme), Wild Child (Kyle Gibney), Shard and Sabretooth (Victor Creed).