Graydon Creed

Graydon Creed is the human son of Mystique and Sabertooth who acts as one of the X-Men's greatest opponents due to his hatred of mutants, which has him lead the anti-mutant organisation known as the Friends Of Humanity.

Origins
At some point during her many travels Mystique would have a relationship with Victor Creed, better known as Sabertooth, the result of this relationship was Graydon - despite both parents being mutants he was born (and remained) human, Mystique would give him up for adoption soon after his birth and later in life Graydon would learn of his heritage and became deeply embittered towards mutants.

Friends Of Humanity
When he reached adult life Graydon had let his resentment boil into outright prejudice against all mutants, seeing them as evil and corrupt - his hatred was sufficient enough for him to form the Friends Of Humanity, a group dedicated to opposing mutant rights via terrorising peaceful mutants and humans that supported them while also playing on the fear caused by mutant criminals such as Magneto to further their own schemes and gain public support.

Death
Graydon Creed would remain a great opponent of the X-Men for many years until his eventual assassination during a rally in which he was trying to gain support to become president - at first the killer was unknown but would ultimately be revealed as a future-version of his own mother, Mystique, having travelled back to prevent the reign of Friends Of Humanity in her timeline and get revenge on her son for the wrongs he commited.

Return
Graydon would remain dead for quite some time before a group of anti-mutant supporters known as the Purifiers would dig his body up and revive him using a techno-organic virus.. this newly revived Graydon would presumably be some kind of cyborg now but it's kind of hard to be certain, at any rate it seems that thanks to the action of the Purifiers Graydon Creed has cheated death and is ready to continue his violent crusade against mutants and those that aid them..