Oscar is the main character of the story. He starts out as a stray Kishu puppy living in a barrow near an arena where he watches the Tosas fight. A teenage human comes around his barrow and adopts him as his pet, giving him a new home. Oscar is trained to be a fighting dog and he beats the first dog he fights at the arena, the elderly Tosa, Rikiya. His father teaches him the attack, the Pou Supuritta and thanks to that, his enemies start fearing him. However, one enemy doesn't fear him even if he knows his father's special attack. The wolf, Ookami who is one of Kudie's followers is in high attempt to kill Oscar and force his father to teach him his attack. Allthough, he doesn't know that Oscar has his own attack, the Zugaikotsu Funsai-Ki which he used to defeat Rikiya.
One day, Oscar enters a match with Ookami. He performs the Pou Supuritta on him, defeating him easily in the first round. Even before the fight ends, he kills the wolf by performing the Zugaikotsu Funsai-Ki.