Hira is a young man who was a kenjutsu student at the Kamiya dojo under the tutelage of Kamiya Kaoru until the murder spree perpetrated by the false Hitokiri Battōsai Hiruma Gohei drove him and all his peers to leave. Even after the incident had been rectified, Hira still did not return to the dojo and, roughly two weeks later, went drinking with a fellow former student Satō and began drunkenly harassing townspeople. Picking a fight with a member of the Hishimanji Guren Gang, Hira and Satō drew their practice swords and broke their opponent's arm. With Hira's shoulder also injured, the duo were ill-matched when the remaining gang members appeared for revenge and fled to the protection of the Kamiya dojo, claiming to have been the victims. However, Hira and Satō's true actions were discovered and, after the Hishimanji Guren gang was driven off, they were told to never again hold a sword in their hands and forget that they were ever students of the Kamiya dojo.
Satō and Hira appeared in Act 4 of the manga, but their adventure with the Hishimanji Guren gang was left out of the anime.