Ryō Hattori possesses short, dark brown hair and a medium build, hailing from Mie Prefecture. A descendant of the Shinobi clan historically charged with protecting shrine maidens, this legacy defines his role as the dedicated bodyguard of Ōka Myōjin, the shrine maiden fated to save the world. He relentlessly trains in sword fighting and diverse physical disciplines to maintain peak combat readiness.

Loyalty, strict self-discipline, and a coolheaded, realistic demeanor characterize his personality. Typically dry and reserved, he exhibits heightened emotional responses specifically when confronting Oni, the supernatural entities threatening humans, underscoring his profound commitment to protection. As a fighter, he relies on honed physical skills and tactical intelligence to combat Oni alongside allies like Kaede Naruse and Haruko Yamada, serving as the team's reliable leader who coordinates efforts to neutralize threats targeting Ōka.

His development involves interactions with Kakeru Miwa, a high school student drawn into the conflict. Ryō initially prevents Kakeru from engaging in dangerous Oni battles, reflecting his cautious, protective instincts and prioritization of safety and structured protocols over impulsive heroism. His protective nature intensifies towards Ōka, whom he safeguards both from clan duty and deep personal loyalty. His leadership demands balancing team strategy with unwavering focus on Ōka's safety during confrontations.