Universe/Timeline:
Marvel Universe
Factor Three was a mutant organization gathered by the so-called Mutant Master, allegedly in the name of mutant supremacy. Unbeknowst to the other members, Mutant Master was actually a Sirian, who intended to use a mutant revolution to destabilize the nations of Earth in advance of an alien invasion. He was uncovered by his lieutenant, Changeling, and Factor Three and the X-Men joined forces to defeat the Mutant Master.