After a young Oni wanders away from his barbaric tribe, he finds himself in Mito, Japan. Legend has it that he developed a Kōdōkan Judo style with the help of Kanō Jigorō, the founder of Judo.

With his newfound martial arts techniques and natural oni strength, he quickly became the toughest Oni. Although his communications skills were still lacking compared to a human’s, his intelligence was significantly higher than the rest of the Oni tribes.

Eventually, the young Oni went undefeated and found no worthy challengers until he met his match with Masahiko Kimura, the All-Japan Judo Champion. Even with his enhanced Oni strength, he was unable to defeat Masahiko. Overwhelmed with shame, the young Oni fled Mito in search of his home tribe. His loss was engraved into his mind and he utters his first word ‘Kimura…’. If he could not be the best at the Kodokan Judo Institute, he believed he could rule over the Oni as their new leader.

Without warning the young Bushido Oni left the region and battled his way to the top of an Oni tribe with the help of the stolen move, the Kimura. The Oni tribes began repeating him, chanting “Kimura!” as he became the victor and rightful leader.

The chants grew so loud that nearby tribes overhead the shouts and began whispering the words “Kimura…” in confusion not knowing the Bushido Oni would inevitably be their ruler. He would continue his conquest, no longer in search of his family but on a quest to dominate the tribes and be known as the leader of all the Oni.