Shinbee, the son of a wealthy merchant, quickly befriends Rantarō and Kirimaru at ninja school. His appearance features an overweight build and a frequent runny nose. He processes thoughts slowly, relying on friends for correction, yet wields notable physical strength. He exhibits a strong preference for consuming large quantities of food. On certain occasions termed bad hair days, his hair stiffens into porcupine-like quills, functioning defensively or as a weapon. His runny nose occasionally serves practical purposes.