Fubuki Kai, a self-made ninja, first challenges Miko Mido to prove her superior talent and claim the future headmastership of the Miroku clan. Defeated by Miko in a sexual duel, she undergoes a profound metamorphosis. Adopted by the demonic Shikima race and converted into one of them, she gains the power needed to rival Miko, embracing and appreciating her new demonic form.

Transformed, she becomes Miko's ally, though their relationship remains complex. Fubuki persistently outmaneuvers or outperforms Miko, frequently irritating her. Her role grows during later conflicts, aiding against threats like the Mahoroba clan and assisting in the recovery of stolen artifacts critical to the Shikima Realm. She consistently employs her abilities and demonic form in these battles. Demonstrating adaptability, she once utilized modern technology, creating a website to locate potential allies for the Miroku clan.

Her background lacks familial connections or early history. Her development focuses on the shift from rival to companion, maintaining a competitive dynamic with Miko. Participation in spin-offs or extended narratives introduces no additional backstory, character changes, evolution in powers, or personal goals beyond her interactions with Miko and the Shikima within their shared endeavors.