Hayato Suo serves as a vice-captain of Bofurin at Furin High School, a group protecting their town. He possesses brown, curtain-like hair and brown eyes. His typical attire layers the Furin High uniform over a light-colored changshan, loose black pants, and flat cloth shoes. A leather eyepatch covers his right eye; he playfully claims it seals a Chinese dragon. Yellow tassel earrings with red gems accessorize his look. Suo favors comfortable Chinese-styled clothing crafted from hemp and silk and often carries small coin purses.

Suo maintains a perpetually calm and smiling exterior, rarely revealing irritation or negative emotions even under pressure. This unflappable demeanor masks a complex personality. He exhibits a refined, aristocratic manner without overt superiority and wields a sharp, analytical mind, adept at manipulating others to gain information or favors. His constant calm unnerves people and obscures his true intentions. Though some call him a "gentleman," a ruthless streak surfaces in combat where he displays a sadistic enjoyment in psychologically breaking opponents. This duality emerges when defending those he perceives as vulnerable or punishing individuals he deems immature or unfair, reflecting his strong belief in empathetic and fair conduct, particularly from adults.

In fights, Suo employs a unique martial arts style focused on evasion and precision. He avoids using fists, favoring palm strikes and evasive maneuvers blending elements reminiscent of Aikido and Kung Fu, taught by a self-taught master for adaptability. Throughout the series, he remains untouchable in battle, using his skills to protect others or enforce his moral code. Outside combat, Suo practices daily meditation and adheres to a disciplined routine, including a specific diet. He avoids group meals and refrains from using his phone in front of others, behaviors that fuel speculation about his detachment or potential hidden loyalties.

Suo holds significant relationships within Bofurin. He is Haruka Sakura's right-hand man and class co-delegate, frequently teasing Sakura while demonstrating deep care. Suo recognizes Sakura's loneliness and encourages him to rely on others. With the other vice-captain, Akihiko Nirei, Suo acts as a mentor, acknowledging Nirei's strengths while teaching practical self-defense techniques like the pillbug position to compensate for Nirei's physical limitations.

Suo's background remains largely unexplored. Concrete details about his family, origins, or the reason for his eyepatch are absent. His refusal to bond over meals and enigmatic behavior—such as speaking multiple languages, collecting global teacakes, and avoiding personal disclosures—hints at a potentially tragic past or undisclosed motives. This ambiguity leads to theories about him being a mole for rival groups or grappling with unresolved personal history. His development shows increased protectiveness, especially toward Nirei, and subtle shifts toward group integration, though his core mysticism persists.