Masaru Hongo is the goalkeeper and initial captain of the Kitahara Elementary School soccer team, preceding Kakeru Daichi's arrival. Initially asocial and detached, his interactions with teammates and shared experiences transform him into the team's emotional anchor, offering stability during moments of peer self-doubt. He leads with restraint and a firm belief in the team's potential, emphasizing perseverance through early losses and internal conflicts.

As one of the team's oldest members, he naturally assumes a guiding role. He harbors romantic feelings for Ayumi Daichi, Kakeru's sister, leading to occasional comedic or awkward situations with the team's interested cheerleaders. While this aspect intersects with team dynamics at times, soccer remains his primary focus. During matches, he exhibits moments of distraction, notably in a game against an all-female team where several players, including Hongo, lose focus due to opponents' attire.

His interactions with rivals like Uesugi of the Red Devils maintain mutual respect, contrasting with his more volatile dynamic with hot-tempered teammate Kenta Ishii. Despite clashes, their shared dedication forges a vitriolic yet productive partnership. His commitment culminates in his departure after graduation, transferring the captaincy to Kenta, signifying recognition of the team's evolving identity beyond his leadership.

The OVA special recaps his journey with the team, introducing no new character developments or background elements beyond the main series.