Touhou Sky Arena: KURENAI is a sequel to the popular fangame Touhou Sky Arena by Area-ZERO. Originally intended to be a series of patches, it was adapted into a full release and was released on May 27, 2012 at Reitaisai 9. A demo was released during Comiket 81.

KURENAI's gameplay is largely the same as its predecessor. Additions include eight new characters and the inclusion of a Spirit Orb system, which allows the player to equip three orbs to their character, modifying their abilities and stats. There are also new levels, including Bhava-Agra, Bamboo Forest of the Lost, an underground cave (not to be confused with Utsuho's stage in the original Touhou Sky Arena), and the Palanquin Ship.