Kamiya Koshijiro was the founder of the Kamiya dojo, the creator of Kamiya Kasshin-ryū and the father of the dojo's current master, Kamiya Kaoru. After fighting in the bakumatsu on the side of the Ishin Shishi patriots, Koshijiro returned to his hometown of Tokyo and developed a kenjutsu style that would protect people rather than take their lives. However, he was drafted into the Seinan Wars and, in 1877, died on the battlefield. His name is not given in the Rurouni Kenshin series, but an identical character with an identical background is mentioned in the Volume 3 End-of-Volume extra chapter. He was voiced by Ikuya Sawaki in the original Japanese version.
Kamiya Koshijiro was said to be a righteous, strong and honorable man, and benevolent at heart, having developed the sword that saves lives than continuing in the tradition of swords that kill. To his daughter however, he is said to be a fierce faced demon as a teacher and a father, and emotionally distant; in the time of his wife's death, he is merely seen fiercely training outside of her deathbed. To all of this, it is merely a facade of exercising honne and tatemae, and emotional subtlety to maintain a strong expressive character, as his true feelings at heart shows he dearly misses his wife and cares for his daughter.