Posing as German spy Leni Zauber, Mystique seduced freelance assassin Victor Creed while he was in Germany on a mission. Mystique later gave birth to a normal human child - Graydon - whom she gave up for adoption, although she kept an eye on him.
When Graydon learned of his heritage, that he was the son of two mutants who had abandoned him as an inconvenience, he grew resentful of all mutants, and that resentment colored his outlook for the rest of his life.
Friends of Humanity
In his adult years, Graydon formed a group called the Friends of Humanity, dedicated to opposing mutant civil rights by committing acts of terrorism against peaceful mutants and mutant sympathizers, and using the acts of violent mutants such as Magneto to rally support for their cause. He was also a member of the Upstarts, a group of well-connected murderous youths who were being manipulated by the telepathic Gamesmaster for his own amusement.
At a rally for Graydon's hopeful presidential candidacy, an assassin shot and killed him. A future version of Mystique had fired the shot, having sworn to kill Graydon for his part in the Friends of Humanity's brutal attack on Trevor Chase, the grandson of her lover Destiny.
A group of Purifiers later dug up the corpse of Graydon Creed and took his body their base where it was re-animated by Bastion using the techno-organic virus taken from an "offspring" of Magus. This resulted in Graydon being resurrected and gaining abilities that Cable had when he was infected by a techno organic virus. Later he died again in the battle against X-Men.
Scott Lobdell had originally planned for the Askani Sisterhood to be responsible for Creed's assassination, and even hinted that there were members of the Askani infiltrated on Creed's campaign.
Creed, founder of the Friends of Humanity has a "mutants killed" count of 147. It is unknown if that correspond to the total of mutants he personally killed, or also those killed by his organization.