Marie Claire is an enigmatic young girl with extraordinary abilities that allow her to manipulate fire. She is always by Tendou Kodzunus side, accompanied by the black cat Mephisto. Her work for Munetaka Yagyuu involves causing chaos in order to disrupt the Dragon Stream. However, she was also tasked with observing Kodzunu and acting as a messenger on behalf of her master Yagyuu. Despite being devoted to him, Claire is quick-tempered and childlike, and when provoked or insulted, she becomes enraged. Her eyes bulge, bolts in her body screw out, and greenish fluid seeps everywhere as her face contorts before releasing a devastating blast that destroys everything around her.
In flashbacks during the second season, we learn about Claire's origins at the Rosenkreuz Academy, where she was part of an experiment studying her bizarre ESP-like powers. She ultimately blows up the facility and escapes, being "rescued" by Yagyuu. Her Star of Fate is revealed to explain why she has pyrokinesis, making her the Vessel of Suzaku, one of the Four Gods tasked with protecting Tatsuma Hiyuu.
Claire is a descendant of Honoka from the prequel game Tokyo Majin Gakuen Gehouchou and has no direct involvement in either Tendou Kodzunu or Munetaka Yagyuu, as she was not part of the original story. She escapes on her own from the Rosenkreuz Academy and befriends Tatsuma on the streets. The Magami teenagers help her thwart the scientists before she develops a crush on Tatsuma and becomes like a little sister to Aoi.