A twenty-year-old art student, he is a former student of Shichisei Gakuen, often translated as Academy of Seven Voices, where Ritsu Minami was his teacher. As instructed, Soubi contacted Ritsuka following Seimei's death. He introduced Ritsuka to the world of fighters and sacrifices, declaring that he would be Ritsuka's fighter. Despite their true names being Beloved and Loveless respectively, they fight together, which is considered taboo. This results in a significant loss of strength, with Soubi's marking bleeding during battles. Since meeting Ritsuka, Soubi no longer operates under the Beloved name and has abandoned it entirely.
Soubi seems to know more about Seimei and the circumstances of his death than he lets on. Even though Ritsuka insists that Soubi tell him everything, Soubi refuses. In volume 4 of the manga, he even states, "Seimei is my God." He openly declares living by Seimei's orders but claims to obey every command from Ritsuka.
Many readers and characters label Soubi as a masochist due to his contradictory nature and conflicting statements about pain and control, making his true feelings unclear. A popular theory among readers suggests that Soubi selectively desires punishment only from those he considers worthy and strong, such as Seimei and Ritsuka. Supporting this theory, Soubi rejects Ritsu's offers to control his life.
Besides being labeled a masochist, Soubi is often described as having a shotacon complex. While some argue there is no evidence within the canon to support this, in the anime, Soubi frequently fondles and kisses the twelve-year-old Ritsuka, making their relationship sexually ambiguous. Whether this indicates a broader complex is uncertain, although in the anime, Soubi also shows infatuation with the male Zero twins.
In recent chapters of Zero-Sum Magazine, it has been revealed that Soubi is the imposter Beloved spell fighter. Ritsu referred to Soubi as a "Spare Fighter," meaning he can pair with any sacrifice.
