Medusa serves as an antagonist within the Chimera faction, a group of destructive anthropomorphic beasts. She possesses distinctive purple hair and red eyes, reflecting her gorgon-like nature. Operating within the Chimeras' hierarchy, Medusa seeks to elevate her status by securing significant victories for the leadership. Learning of her subordinate Byakko's defeat at the hands of Soul Eater and Ryuusuke, she specifically targets the weakened Brain Jacker for retribution to prove her effectiveness, successfully capturing her.

In combat, Medusa commands venomous snakes that deliver a potent aphrodisiac toxin. This toxin induces extreme sexual sensitivity and willlessness in victims, stripping them of resistance, a method she uses to subjugate and capture Brain Jacker. Her actions are driven by ambition, not loyalty or vengeance for comrades, evident in her dismissive and condescending treatment of fellow Chimeras like Pegasus, whom she views as tools or obstacles. Personal recognition from the Chimera leadership remains her paramount goal.

Following the capture, Medusa subjects Brain Jacker to prolonged psychological and physical torture instead of immediate execution. This cruel methodology serves both as punishment for opposing the Chimeras and as a demonstration of her prowess, aligning with her role as an enforcer within the faction. Her narrative role centers solely on these antagonistic activities across appearances, presenting her as a secondary antagonist who directly challenges the protagonists and fuels the conflict through Brain Jacker's capture and suffering, with no significant redemption or backstory provided.