Fubuki Kai is a self-made ninja who initially challenges Miko Mido to prove her superior talent and worthiness as the future headmaster of the Miroku ninja clan. After losing a sexual duel to Miko, she undergoes transformation into a Shikima demon following adoption by that race, seeking power equivalent to Miko's. Fubuki expresses fondness for her new demonic form yet maintains a competitive dynamic with Miko, frequently irritating her by demonstrating superior abilities.

As a Miroku kunoichi, Fubuki shares the clan's extensive training in sexcraft ninjutsu, utilizing the body as a weapon through tactical sexual encounters against humans, monsters, or fellow ninjas. This mastery of erotic techniques aims to overwhelm opponents but carries inherent vulnerability to losing control to pleasure during combat.

Her affiliation shifts from the Miroku clan to the Shikima Kingdom post-transformation, though she retains ties to both. Fubuki evolves from Miko's rival into her ally, participating in conflicts against threats like the carnal butterfly demon tribe Mahoroba, which seeks conquest of the Shikima Realm. She operates alongside Miko and others, employing her Shikima-enhanced powers to protect clan interests.

Depicted as a 16-year-old high-school student alongside her ninja occupation, Fubuki possesses yellow/dark blonde hair and blue eyes. Her narrative consistently explores rivalry, transformation, and integration into the Shikima hierarchy.