He is a member of the League of Villains and leader of its sub-group, the Vanguard Action Squad. Dabi - like fellow League members Himiko Toga and Spinner - was inspired by Stain and his ideology, and joined the League under the belief it harbors the Hero Killer's cause. Following the conflict with the Meta Liberation Army, he became one of the lieutenants of the Paranormal Liberation Front, serving as the co-commander of the Violet Regiment.

It is later revealed that Dabi is actually Toya Todoroki (in Japanese 轟 燈矢), the eldest child of the Todoroki family who was thought to have died in a forest fire years ago. Dabi wants to take revenge on his father, Enji Todoroki - the Number 2 Hero "Endeavor" - for being abused and neglected in his childhood, and kill the rest of his family due to believing they forgot about him after his presumed demise.