Marui is a character from the baseball anime and manga series Captain. He is a short-statured student with a distinctive bean-shaped nose, known for his argumentative and blunt personality. Marui serves as the captain of Sumiya High School's baseball team during his own time, and later appears as a former captain who closely follows the progress of his junior teammates. His primary motivation is preserving the legacy and standards of the team he once led, and he is quick to reprimand younger players whom he feels are not living up to that legacy. This is often expressed through physical discipline, such as slapping a junior player with a folding fan. Despite his harsh methods, Marui’s actions are rooted in genuine care for the team’s success and respect for the captains who came before him. He plays a role as a supporting figure who bridges the past and present of the baseball program, offering both criticism and encouragement. His key relationship is with Shigekazu Kondou, the current junior high captain, whom he scolds but also supports during important matches. Marui’s development is seen as he transitions from an active player into a watchful mentor, still deeply invested in the team’s fortunes. In terms of abilities, he is portrayed as a capable and authoritative leader, though specific playing skills are not emphasized in the available material.