Leon grew up with his mother in Arkansas The identity and fate of his father is so far unknown. Leon went to Howard University, but quickly found himself in finacinal trouble. Due to his low grades during the first semester, he wasn't awarded a scholarship trustee, despite his good grades the second term and a position on the football team. He was visited by a government agent who told him that they were aware of his difficulties and that he had been selected for a special program. Believing he had no choice, Leon accepted and became a part of Project: Genesis, a special program of INTERNATIONAL OPERATIONS Leon like all subjects, had been tested positive for the gen-factor substance that could give regular humans superhuman powers. The subjects were fed a special activator drug during the program. Leon's first signs of Gen-activation were a discoloration in his hair, which went from black to yellow. At first he hid his hair and considered shaving it all off, but then he decided to just accept it. He also started to have nightmares and high fever. In the infirmary he was cryogenically frozen.
Interference from Lynch and Project Genesis subjects Gen 13 meant the end of the program and Baiul escaped, taking the frozen subjects with her. Several months later, Leon was the first to be thawed. His powers and competitive nature made him ideal soldier material to Baiul who added him to DV8. DV8's original leader was Threshold, but he and his sister Blisswere never considered part of the team by the other members, presumably because they already were involved with I.O. before Project: Genesis. DV8, nicknamed the Deviants, were sent on many dangerous missions and Baiul always made it clear to them that they were expendable to her. To survive in this lethal environment, the Deviants became tough and amoral. One of the few Deviants to retain any sort of moral compass, Leon became sick of the death, depravity and violence that were a part of being in DV8.
During his time with the team, Leon is telepathically assaulted by one of the more brutal aspects of Copycat's fragmented mind. That aspect plans force him to have sex with her. He only escapes by draining off much of Copycat's heat. During this encounter, Leon reveals that his first sexual encounter was with Bliss and not pleasant at all.
Leon also participates in a mission to save a neigbhorhood from a homicidal drug gang. He was approached by a young girl, who pleads for help. Later, after the gang is neutralized, he learns the girl had been bed-ridden all this time.
When Ivana blackmailed herself back into I.O., the team became I.O. agents. Leon saw this as an opportunity to atone for their crimes and when Threshold betrayed the team, Leon decided to quit. Frank Colby, the I.O. agent who had taken over DV8, convinced Leon to stay and become the new field leader of DV8. Colby convinced Leon that he was the only one all the others in the team looked up to and that without him DV8 would disband. Leon didn't have any loyalty towards I.O., but he knew that Colby was right when he said that some of his fellow Deviants wouldn't be able to survive in the outside world.
On a mission, Frostbite came into contact with the villain Arthrax, who used his addictive touch upon him. During this mission Leon was forced to push his powers beyond their previous limits and was taken back, seriously injured. When he recovered his powers were gone. Shortly afterwards Ivana fired Leon. Outside, Frank Colby talked to Leon and asked him to join a conspiracy against Ivana. Leon, who was sick of Ivana and her ways, agreed and went home to his mother. There Colby's men exchanged Leon with a body-double and transplanted the tracker Ivana had implanted in all DV8-members to the double. Ivana had the double killed shortly afterwards and Leon was now officially dead. Colby's men introduced Leon to his fellow conspirator, Stephen Callahan, father of Threshold and Bliss. With Callahan's help, Leon's powers were restored. Shortly afterwards DV8 member Sublime joined the conspiracy as well and they went against Ivana and I.O. The battle would mean the end of DV8.
Leon joined Sublime and Copycat to try and lead a normal life. They were joined shortly afterwards by Genevieve Cray, a female clone of Michael Cray, Sublime's father. Under Cray's leadership the group battled the villain Trance and his group. Trance captured Leon and Sublime and used his mind-controlling powers to make them kiss each other. Frostbite and Sublime had had some sexual tension towards each other for a long time and Trance noticed this. He ordered them to go further when Cray and Copycat stopped him. Trance and his team were defeated, but Leon and Sublime admitted to each other that it hadn't been all bad and tentatively started a relationship.
Ability to absorb heat from any object leaving it frozen solid. He can also store heat inside him and release it as blasts of heat. He has limits to the amount of heat he could absorb and store and he used to wear a special belt and gloves that helped him control his powers.