Badger Hero: Brute Ratel

Hitomi, along with various other children with animal-based transformation quirk(s) that become orphans, or were abandoned by the people that they once cared about were experimented and drugged once the moment came for their quirk(s) to develop. For years as the children were researched by the doctors and nurses, once they become a certain age, the children are tested by undergoing battle trials. An illegal underground fight club called "Killing Bites," between the children/teens going no matter their age went head-to-head with one another in reigning supreme, and then sold on the black market auction as super soldiers of such for the mafia and villains. For it was either kill or be killed if you refuse to accept your fate.