Touka is the protagonist of the series and the child of Yumiko Kamiazuma. He has the sacred Stone sword within his chest. Some believe he is the reincarnation of Isabihiko, the former owner of the Stone Sword. In reality, he is a non-human replacement of Yumiko's lost daughter, who is also named Touka, and the Stone Sword is an integral part of his body.

Despite his cold attitude towards Momoka, they have a very close relationship to the point where he finds her to be one of the most important people in his life. He also usually always gives in to Momoka's requests. It is later revealed that he does, in fact, have feelings for Momoka.