Once a glorious clan, Suigen has weakened considerably in recent years, almost leading to its extinction. However, with the addition of Kagetora and Suiren, the clan is on the road to complete revival.
Protagonist. Known as "Kage Oni", one of the 4 Oni of Suigen clan. He doesn't have the talent necessary to be a proficient ninja, but his management skills and his ability to entice female opponents to betray their clan are top-notch.
Known as "Sen Oni", one of the 4 Oni of Suigen clan. Suiren serves as Kagetora's bodyguard. She is feared by the enemies because of her prowess in combats. However, she is better off in solo missions than in group battles.
Known as "Metsu Oni", one of the 4 Oni of Suigen clan. Usually disguised as a merchant to collect information throughout the land. Along with Hayate, Onimatsu was among the first to notice Kagetora's talents.
Hotaru is the leader of a team that is sent by Taki clan with purpose to attack Suigen. Due to her fairly low position in the hierarchy within Taki, Hotaru is undervalued by her peers despite of her good abilities.
Matsurika is the leader of Fuka clan. Everyone looks up to her because of her reliability and prowess in both academic and skills, which inevitably draws the line separating herself and her sister, Sekka.
Mitaka is the daughter of one of Kurutaki House's officials, serving Sakura-hime faithfully. While skilled with swords, she knows next to nothing about politics. She is a tough warrior and known to be resilient.