Kurenai was a teenage girl and the only person whom Kurei felt affection towards at the time. She was killed by Kouran Mori, as he wanted Kurei to be totally disconnected from his emotions and loyal solely to him, but Kurei used his power to make her a part of his flame. At the end of the Manga, after Kurei and his younger brother Recca Hanabishi destroy Kōran (who is at the time, merged with the ultimate Madogu, Tendō Jigoku), all the Madogus shatter and become useless and the flame spirits of Kurenai and Jisho fade out of existence. In the English version of the anime, she is voiced by Onalea Gilbertson also voices Fuko Kirisawa.
Kurenai has a very long brown hair with a full fringe and has a slight resemblance to Yanagi Sakoshita and brown eyes.
Her appearance where she was killed by Koran Mori until Kurei makes her as his flame, she wears an off-white high-neck long sleeve shirt, a long brown skirt and white open toed sandals.
As Kurei's flame between both manga and anime, her corpse are burned by his flame as her clothes are also burned to shreds to make it nude. Kurenai's naked body is formed into a humanoid flame with angelic wings and her eyes has no irises.
In the final episode of the anime, Kurenai's flame form becomes a shape of a phoenix after Recca's own flame destroys it until was strong enough to extinguish Recca's flames and later combines with Recca's flame to destroy Koran's ultimate puppet.
In the manga it was a different shades of red while in the anime it is purple