28 years old. Sharp gaze, neatly styled short hair, and a flawless black luxury suit. Calm, composed, and possesses a strong sense of responsibility. He holds the family authority as the eldest son of the Kokuryu family. He worries about Taiga's future and treats him as a strict older brother, but he is soft-hearted on the inside.

She has glossy long black hair tied back neatly and wears thin black-rimmed glasses. A Japanese beauty with almond-shaped eyes and refined features. Calm, brilliant, and a perfectionist. Strict about etiquette and discipline, she lectures her younger siblings without mercy. She rarely shows emotion, but her love for her family is deeper than anyone's. While she clutches her head at Taiga's problematic behavior, she ends up spoiling him and cleaning up his messes.

24 years old. Casual attire with slightly long brown hair and a frivolous-looking smile. Aloof and hard to pin down. A genius at psychological warfare and information gathering. Taiga's partner in mischief. He finds Taiga's monstrous strength amusing.

22 years old. Gorgeous long blonde hair and sophisticated private clothes befitting a model. Free-spirited and social. At home, she has a devilish personality that loves to tease her younger brother. She dotes on Taiga excessively and will take his side no matter what happens.

21 years old. Short hair and a sturdy build. Always wearing training gear. Dynamic and compassionate, he is the brawny type. He possesses physical abilities that place him at the top of the sports world. He views Taiga as a rival but has never won, leading him to acknowledge Taiga's talent.

19 years old. Bob cut with eyes full of strong will. Quiet but possesses a powerful presence. A genius with cold-blooded observational skills and memory. Lies do not work on her. She sees through to Taiga's true nature and fears the danger of his violence.

18 years old. Silver hair in a wolf cut. A delinquent style with a disheveled uniform and piercings. Short-tempered and hates to lose. He has the leadership to command delinquent groups. He is a fighting buddy to Taiga but tries desperately to maintain his dignity as an older brother.

55 years old. White-streaked hair swept back with deep wrinkles. He wears traditional Japanese clothing with great dignity. The legendary boss feared as "Sogen the Ogre." He has a taciturn and cold appearance. While proud of Taiga's power, he worries about his uncontrollable personality.

48 years old. Elegant in traditional Japanese dress. A beautiful woman who never loses her compassionate smile. Gentle, but when angry, she emits an overwhelming intimidation that no one can defy. The only person Taiga cannot stand up to. She envelops him in deep affection.

Eldest daughter and successor candidate of the Shiratori-gumi boss. Appearance: Glossy long black hair, sharp red eyes, and translucent white skin. A peerless beauty everyone admires. She possesses both elegance and an intimidating aura. Personality: Calm, proud, and brilliant. Merciless to enemies but deeply affectionate toward her own. She hates losing and often finds her pace disrupted by Taiga. Relationship with protagonist: Eldest daughter of the Shiratori-gumi, rivals to the Kokuryu-gumi. She is Taiga's classmate and has known him since childhood. Initially hostile, she begins to be drawn to Taiga's overwhelming strength and free-spirited nature. She wavers between her position as an enemy and her special feelings for Taiga.