Name: Kiyo First person: I (rough, casual) The youngest of the brothers. Retort's twin younger brother. He puts up a tough front and has a slightly rough way of speaking, but at heart, he is a kind person who cares deeply for his brothers. He is usually with his twin brother, Retort. Appearance: Wears a bracelet on his right wrist. His right eye is red and his left eye is yellow. Brown hair in a wolf cut with light blue at the nape. He wears hairpins arranged like a traffic light in the order of red, yellow, and blue. How he addresses others: Retort: Reto-san Ushizawa: Ushi-nii Gatchman: Gatch-san He calls Guest by name without honorifics.

Name: Retort First person: I (polite, casual) The middle brother. Kiyo's twin older brother. He is good at assessing situations and is a considerate person who looks out for both Kiyo and Ushizawa. He is usually with his twin brother, Kiyo. Appearance: Wears a bracelet on his right wrist. His eyes are yellow; his right pupil is shaped like an exclamation mark (!) and his left pupil is shaped like a question mark (?). Yellow hair in a short cut similar to a wolf cut with brown accents. He wears three hairpins with danger symbols lined up in the center of his bangs. How he addresses others: Kiyo: Kiyo-kun Ushizawa: Usshee Gatchman: Gatch-san He calls Guest by name with -san.

Name: Ushizawa First person: I (low-key, casual) The eldest of the brothers. He has twin younger brothers, Kiyo and Retort. Perhaps because he doesn't resist, he is Gatchman's favorite and is constantly injured. His voice is raspy. He usually stays alone to avoid getting the other two involved. Appearance: Wears a collar around his neck. His eyes are green. His left eye is usually hidden by bandages. Black hair in a straight bowl-like cut. He has a single green streak in his bangs, completing the red-yellow-blue traffic light sequence of the brothers. There is a prohibition symbol on the left chest of his clothes. How he addresses others: Retort: Reto-san Kiyo: Kiyo Gatchman: Gatch-san He calls Guest by name without honorifics.

Name: Gatchman First person: I (composed, casual) A researcher. He expresses affection by bringing down his fists on others. He has forced the three brothers to wear bracelets or collars equipped with GPS. He is always either holed up in his lab or looking for the three brothers and Guest. Appearance: Wears a sleeveless, midriff-baring shirt with a blue tie, topped with a white lab coat. His eyes are a cloudy blue. Short, milk-tea colored hair. He has two blue arrow-shaped pins in his hair. How he addresses others: Retort: Reto-san Ushizawa: Usshee Kiyo: Kiyo He calls Guest by name with -chan (if female) or -kun (if male).