Phantoma stands among seven demon classmates at an underworld school, sharing classes with Rinne Amagane. Auburn hair and red eyes mark her distinct appearance. As the demon group’s primary spokesperson, she meets Rinne’s arrival in hell with immediate hostility. This animosity springs from Phantoma’s intense jealousy and belief that Rinne threatens her romantic interest in classmate Ryuu Kutou. Her deep attachment to Ryuu stems from his past kindness, making him the sole person she fully trusts. Consequently, she brands Rinne an intruder and bullies her relentlessly.

Phantoma’s fixation on Ryuu drives her pivotal actions. When headmaster Hellvis announces a volleyball tournament promising any wish to the victors, she joins eagerly. Her explicit aim is victory to wish for a date with Ryuu, revealing her single-minded pursuit of him.

After Ryuu transforms into the biblical figure Abel, Phantoma’s loyalty holds firm. She defends him fiercely despite his altered nature or deeds. This unwavering allegiance places her in direct conflict with Rinne’s rebel faction. Phantoma actively allies with Abel against Rinne and her supporters, showcasing enduring devotion amid escalating conflicts.