Tōka is the protagonist of the series and the adopted child of Yumiko Kamiazuma. He has a sacred, soul-eating blade, called the Stone Sword within his chest. Some believe him to be the reincarnation of Isamihiko, the former wielder of the Stone Sword. In reality, he is a non-human replacement of Yumiko's lost daughter, (who was also named Tōka) and the Stone Sword is an integral part of his body, since he was specifically born to wield it.
Tōka has two different forms in the series. As Yumiko's daughter, he has long hair and wears a red kimono, while normally he is short-haired and wears casual black shirt and trousers, or a school uniform. Regardless of his outer appearance, his personality is always rather blunt, callous and short-spoken. The only people he seems to care about are his adoptive mother, Yumiko, and Momoka.