Kuonji Souji

He has been sexually abused by both parents and his older sister, Kasumi, and currently committing incest with his younger sister, Asuka. The only time he shows any glimmer of emotion is during sex, although he remains stoic when Asuka copulates with him. Memories of being raped still plague him often, and he finds himself being additionally tormented by nightmares of a mysterious woman who tries to both rape and kill him.

He flatly dismisses Asuka's friend Mayumi after he takes her virginity, and forces himself on Makoto after she is assaulted by several female members of their kendo club, seeming to revel in dominating her. Sōji's heart begins to thaw after a fateful coupling with Mizuki; fed up with his abuse, she slaps and berates him. He responds by trying to strangle her, stopping only when he gets flashbacks of choking out the dark-haired woman from his nightmares. Completely shaken, Souji releases Mizuki and apologizes tearfully. He later apologizes to Mayumi for the way he had treated her, tries to apologize to Makoto (who ignores him when he calls out to her), and begins a real relationship with Mizuki. By the start of Kokoro II, Sōji and Mizuki had married, and Souji had taken over as president of the family business.