Cooan is the youngest of the Ayakashi Sisters, though she's the oldest in the English dub. She wields "Dark Fire" (called "Ice Fire" in the dub) and basically functions as the Black Moon's twisted answer to Rei Hino.
In the manga, Cooan approaches Rubeus sensing a kindred fire spirit who might be recruited. Armed with "Code001, Operation Re-cruit," she infiltrates a girls' academy by posing as a student and establishes a paranormal club under the Black Moon's banner. She's unsettling—cold hands, colder eyes. At a school festival, her fortune-telling booth takes a dark turn, predicting clients' deaths while promising a "better" one for Black Moon followers. When Rei transforms into Sailor Mars to fight her disguised droid army, Cooan reveals herself and unleashes fire. She gets taken down by Sailor Moon and Tuxedo Mask's combined attack, though not before abducting Mars.
In the anime, she's almost unbearably vain—genuinely threatening death over smudged makeup. She's convinced she and Rubeus are an item and constantly jockeys with her sisters for his attention. Her worldview centers on being loved rather than loving, which puts her at odds with Rei's take on relationships. When Rubeus gifts her cologne only to crush it and threaten her with execution if she fails again, viewers get a hint of what's coming.
The turning point hits when Chibiusa arrives. Cooan fails to kill her, and Rubeus coldly reveals he never cared about her at all—handing her a time bomb as a final insult before walking away. Sailor Mars's intervention saves her, and Cooan snaps out of her spiral when Mars gets hurt protecting her. Sailor Moon purifies her with the Silver Crystal, and she returns to human life. From there, she becomes an unlikely ally, talking her sisters out of suicide missions and helping them realize they're all being manipulated by Rubeus.
Content compiled by AnimeList.moe from publicly available sources.
