Munehiro Kabaji is a second-year student at Hyotei Academy and one of the regular members of its tennis team. He is the tallest member of the club, standing at 190 centimeters and weighing 85 kilograms, with slightly dark skin and black hair with small spikes. Kabaji rarely speaks and is most often heard responding to his captain, Keigo Atobe, with a simple "Usu," meaning "yes" or "yup." He has been following Atobe since the age of four, having transferred from King's Primary School to Hyotei's elementary division alongside him, and he serves as Atobe's loyal right-hand man. Kabaji holds deep respect for Atobe and is constantly seen a step behind him. Despite his imposing size and quiet demeanor, he is a powerful and adaptable player. His mental strength is formidable; he does not react to opponents who try to intimidate him, as seen during matches against aggressive players. Kabaji's signature ability is Perfect Copy, which allows him to observe an opponent's techniques and replicate them flawlessly during a match. Because of this, his play style has no fixed type and changes depending on the opponent. He is also known for his exceptional stamina, speed, and raw power, making him a reliable asset in doubles and singles matches. His personal interests include assembling bottle ships and making dollhouses, and he has skills beyond tennis such as ironing and patchwork. He dislikes being told to say something interesting and spends his allowance on nothing in particular. Kabaji's role in the story is that of a steadfast supporting player for Hyotei, often acting as Atobe's partner in doubles or as a solo player in critical matches. His relationship with Atobe is the defining bond of his character, but he also interacts respectfully with teammates such as Jirou Akutagawa, whom he helps wake up, and he shows a gentle side when he builds a dollhouse for another teammate's dog. Throughout the series, Kabaji demonstrates consistent loyalty and quiet dedication, and his simple-minded, observant nature proves to be a strategic advantage on the court. His stated motto is that even a tiny insect has half a soul, meaning one should be considerate of the weak.