When Victor Creed's mutation first manifested, he accidentally killed his brother over a piece of pie. His father confined him to a cellar and would systematically pull out Victor's "devil teeth" in an attempt to purge the boy of his "demons". Victor was chained like an animal in the family cellar for years until one day he chewed off his own hand in order to break free, subsequently murdering his father. Although he would later claim to have killed his mother as well, he actually spared her, and made sure she lived a comfortable life, until she was diagnosed with cancer and confined to a hospital, where she was killed by a member of the Red Right Hand. Freed from his parents, Victor was unleashed upon society.

Sabretooth is a vicious killer who delights in inflicting pain and misery. Like his rival Wolverine, Sabretooth has an animalistic side, but whereas Wolverine fights to control himself and his murderous rage, Sabretooth has no qualms in giving in to his base instincts. He gives himself over wholeheartedly to the beast within and indulges in every vile or murderous impulse that strikes him. While Sabretooth has been part of teams such as Team X and the Marauders in the past, he is wholly self-serving and will readily betray anyone to save his own skin or achieve his own goals.

Enhanced Mutant Physiology: Sabretooth is a mutant who had been given artificial enhancements on multiple occasions by various backers. The O*N*E classified him as a Severe Threat.