Cooan

Cooan is the youngest of the sisters with the attack called "Dark Fire", and represents a counterpart of Rei Hino. Her name is short for kouankou, the Japanese word for kermesite. In the manga, Cooan tells Rubeus she feels someone like her that is kindred to fire and could be convinced to join the Black Moon. Rubeus gives her "Code001, Operation Re-cruit" to convert humans to their cause. She poses as a student named Kurozaki Cooan at the T*A Girl's Academy where Rei Hino attends and becomes the leader of a paranormal club called the Black Moon.

In the anime, Cooan is, like all of her sisters, very vain about her appearance to the point of swearing death upon anyone who smudges her make-up or ruins her hair, and she relies on her charms to get what she wants. She believes that she and Rubeus are in a relationship, and competes with her sisters for his love.