- See also: Demon Crimson
|Season||Sky Pretty Cure|
|Debut||Sky Pretty Cure 33|
|Last Appearance||The Final 10|
Kuro Crimson is a Pretty Cure of the Sky Pretty Cure Series and the corrupted alter ego of Akahane Ruby. Kuro Crimson had her only appearance in episode 33 and 34 of the first season and made cameo appearances in episode 35 and episode 36 of the second season. Kuro Crimson did use attacks in the episodes but those weren't named. Kuro Crimson also made an appearance in the final season, in The Final episode 10.
- Main article: Kuro Crimson / History
As Kuro Crimson her hair has the length of her civilian hair, while the color resembles Crimson's. Her eyes seem soulles and have the same color as Crimsons. She wears a black dress with a dark red collar. It is laced down with red laces. She wears a black skirt. She wears a red belt with a star-shaped buckle and a grey, flame-shaped cloth attached to it. She wears black boots of which the left one goes over the knee and the other one doesn't. She wears net-arm warmers around her left arm and a dark red, fingerless glove at the right hand.
- Blaze up, my black passion! (燃え立つ、私の黒じょうねつ！?) - The spell Kuro Crimson used to change from Cure Crimson into her dark appearance.
- Fire of Darkness (闇のファイア?) - One of the attacks Kuro Crimson can use. To summon it, she calls "Come to me, Fire of Darkness!" and a circle of purple fire appears around her. She then is able to shoot it at the enemy as a whole or as many small fire balls.