Sera Nobuaki

He loved his sister as a woman. At some point of time, he confessed to her, but she told him that "she loves strong men". Therefore, Nobuaki started to try his best to improve himself and become stronger, carving out his attractive points and his true nature. But it had no effect. Dark emotions began to stir in his heart. He became envious of his sister, even becoming tempted to plunge her into the darkness so they could go into Hell together. To not allow himself to actually do this, he committed seppuku. But his despair at the brink of death summoned a demon, Shinno Akikage, who inherited his desire...