Ryouma is a member of the ancient Fūma Clan, locked in a centuries-long conflict with the rival Yasha Clan. He arrives at Hakuo Academy with fellow Fūma ninja to aid protagonist Kojirou after the Yasha Clan allies with rival school Seishikan.

A stoic and disciplined warrior, Ryouma strictly adheres to the Fūma code, frequently invoking "Shinobi Law" as his guiding principle. This rigidity shapes his tactical choices during battles against the Yasha Generals. His combat style includes the visually distinctive "Fuma Shikyoken" technique, enhanced with digital effects in adaptations.

His relationship with Hakuo Academy student Ranko Yagyū marks a significant arc. Her acts of kindness challenge his detached demeanor, prompting him to gradually acknowledge his own humanity beyond being a clan weapon and softening his initial rigidity.

Ryouma participates in key battles throughout the conflict, notably facing Musashi Asuka, the Yasha Clan leader. Their confrontations receive greater narrative focus than other clashes, highlighting Ryouma's importance within the Fūma ranks. Following the deaths of Fūma members Kou and Rinpyo during the war, Ryouma continues fighting alongside surviving comrades like Kirikaze and Ryūhō in subsequent conflicts against the New Fūma Clan.

Details regarding his origins, early life, or specific activities outside the depicted conflicts remain undefined within the available sources; his background prior to arriving at Hakuo Academy is similarly undefined.