Formerly a prodigy child actress, Kana Arima lost most of her footing in the entertainment industry due to the poor reputation she garnered for herself on set during her grade school years. Though her attitude has greatly reformed by the present day, her image as merely a washed-up child actor continues to hamper her efforts.

Ryou Asuka is the best friend of Akira Fudo, the protagonist of Devilman. Though the two were separated after Akira switched schools, they were reunited when Ryou sought Akira's help to stop the demons which had begun to reappear in the world. In order to better their chances of success, Ryou suggests the two of them fuse themselves to become a devilman—heart of a human, but the body and power of a demon—though only Akira is successful. As Devilman, Akira works with Ryou to fight the increasing onslaught of demons.