Kyle Gibney is a
mutant who manifested a
feral mutation during
puberty; this mutation grants him enhanced physical abilities, an increased rate of regeneration, and a bestial appearance. This prompts his parents to throw him out of their house. Living on the streets, he is kidnapped by the conspiratorial
Secret Empire and subjected to experimentation that alters his mind and body, making him mentally unstable and prone to violent and animalistic behavior. During this time, he becomes acquainted with
Valerie Cooper, a
United States government official who is unaware of the Secret Empire's true nature or activities. He is freed by
Wyre, a man who has unwittingly been the source for the genetic material used in the Empire's experiments. Gibney (now Wild Child) is detained by the military and taken into the custody of
Canada's secret
Department H, which oversees the formative
Alpha Flight team. Flight member
Walter Langkowski, wanting to protect Wild Child from the military, places him in the trainee team dubbed
Gamma Flight. After Alpha Flight and its trainee groups are disbanded, Gibney is recruited to join
Omega Flight. Wild Child is given membership in the new Gamma Flight. When Gamma Flight is disbanded, he goes berserk over his deprecated status and attacks
Pathway, another trainee. Gamma's leader
Nemesis teleport him away during a fight with Heather Hudson (
Guardian) and
Wolverine, and he is captured by Wolverine. Department H helps him overcome his psychological problems, trains him in unarmed combat, and places him as a special operative of the Canadian government assigned to Alpha Flight under the codename Weapon Omega. Wild Child later defeats Wyre in personal combat; he then learns about his true origin, and changes his codename to
Wildheart. He follows Valerie Cooper to the United States, where he joins X-Factor. There he begins a romantic relationship with his teammate
Shard. His teammate
Sabretooth unsuccessfully attempts to convince Wild Child to become a hunter and killer like himself. Wild Child degenerates to a near-mindless state and is recruited into the new
Weapon X team. As part of his draft into Weapon X, Wild Child is paired with Sabretooth to try and recruit
Sunfire to the program. However, he refuses and badly burns Sabretooth. When Wild Child mocks his burns, Sabretooth slits his
vocal cords, leaving him mute. His past flame, Aurora, is later recruited into the team but is not herself. She becomes cocky and aloof, snubbing Wild Child and engaging in a relationship with Weapon X director
Brent Jackson. Wild Child is one of the mutants depowered after
M-Day. His energy signature is found within the
Collective, along with the energy signatures of many other depowered mutants. It is later revealed that Wild Child regained his powers and his previously erased memories, along with his capability of speech. In the new status quo for mutants post-
House of X and Powers of X,
Professor X and
Magneto invite all mutants to live on
Krakoa and welcome even former enemies into their fold. Wild Child joins a loose group of outcast mutants, operating under
Mister Sinister: the
Hellions, which also include
Havok,
Kwannon,
Empath,
John Greycrow, and
Nanny and Orphan-Maker. During a mission to
Arakko, the Hellions encounter
Tarn the Uncaring and his Locus Vile. In the ensuing battle, Wild Child is killed. He is resurrected, albeit stronger and with a more aggressive and impulsive personality as a result of dying in the dimension of Amenth. ==Powers and abilities==