Summary
Cooan is the youngest sister, though she is the eldest in the English dub. She wields the Dark Fire technique, known as Ice Fire in the dub, and serves as a counterpart to Rei Hino. Her name is derived from kouankou, the Japanese term for kermesite. In the manga, Cooan confides in Rubeus about sensing a kindred spirit within fire who might be persuaded to join the Black Moon. Rubeus assigns her Code001, Operation Re-cruit, a mission to recruit humans. She assumes the identity of student Kurozaki Cooan at the T*A Girl's Academy, where she leads a paranormal club called the Black Moon while Rei Hino attends. Another supernatural club leader is unsettled by her cold hands and eyes, and a black saucer-shaped object is seen flying away after she departs. Rei suffers a nightmare in which Cooan uses her powers to burn a child's body. During the school's culture festival, Cooan runs a fortune-telling booth, predicting the death of her clients but telling Rei that those who follow the Black Moon will die better. When Rei discovers droids disguised as nuns, she transforms into Sailor Mars and defeats them, causing Cooan to reveal herself. In the resulting battle, Cooan blasts Sailor Mars with fire, but Sailor Moon and Tuxedo Mask kill her using the Cutie Moon Rod. Mars, trapped in the flames, is then abducted by Rubeus. In the anime, Cooan is extremely vain, threatening death to anyone who ruins her makeup or hair, and she uses her charm to manipulate others. She believes she is in a relationship with Rubeus and competes with her sisters for his affection. When she gifts him cologne, he cruelly crushes it and warns that her next mission will be her last if she fails. While scouting Hikawa Shrine for Chibiusa, she mocks the relationship between Rei and Yuuichiro, comparing it unfavorably to her own bond with Rubeus. She engages in a debate with Rei and Usagi, disagreeing with Rei’s view that mutual love is paramount, insisting instead that only the amount of love one receives matters. Her beliefs are challenged when Chibiusa arrives and Cooan attempts to kill her. Yuuichiro and Sailor Mars are seriously injured protecting each other, surprising Cooan given her previous perceptions of them. She fails to kill Chibiusa, and Rubeus appears to judge her. Desperate, she begs for his help, believing their love suffices, but he reveals he never loved her and has no use for her. He hands her a time-bomb, instructing her to kill herself and the Sailor Senshi before abandoning her. The other Sailor Senshi arrive and knock the bomb from her hand, causing it to explode harmlessly in the sky. Enraged and hopeless, Cooan attacks everyone, but Sailor Mars, having been injured protecting Cooan from the other Senshi, convinces her she can have a second chance. Sailor Moon purifies her with the Silver Crystal, turning her into a normal human woman. Later, she convinces her next oldest sister, Berthier, to stop from killing herself and the Senshi after being discarded, and similarly persuades Petz and Calaveras that they are being used.
