Cergy

Toushin Toshi
Cergy was a devil who once lived in a fortress inside the Trial Dungeon outside of Toushin City. There, she kept up an antagonistic sexual relationship with her neighbor devil, Dalis. During the events of Toushin Toshi, Cergy was contacted by Poe, a contender in the Toushin Tournament, who was in dire need of additional strength. He contracted with Cergy, who possessed him and boosted his abilities, but also directed his mind and turned him into a cruel torturer. Among other events, this led to his public humiliation of his former harrasser, Morris.

While Cergy was happy to remain in Poe for the time being, Poe's beloved, Kurara, contacted their friend Custom and told him what had happened. Custom made a contract with Dalis, who was eager to one-up her rival. The two battled in Poe's mind, and Dalis became victorious, though the battle destroyed Poe's physical form. Cergy's ultimate fate is unclear, Dalis claiming Cergy had "returned to her" and that she would be "mine forever." It is quite possible that Cergy never returned to the physical plane, and has been somehow subsumed by her former junior.