Eisaku Ohtomo is a teenage boy with fair skin, short stature, and dark green hair shaved on the sides but longer on top. He possesses a notably childish personality, his quick temper flaring up when teammates annoy him. He first appears during the Tokyo City Esperion Youth team entrance exam, meeting Ashito Aoi. Initially nervous in the 7-vs-7 trial match, he lashes out at Ashito for losing possession and playing selfishly as their team falls behind. However, observing Ashito's vision and decision-making, Ohtomo recognizes his potential; their coordinated play results in a goal. Ohtomo passes the entrance exam alongside Ashito and Sōichirō Tachibana. Assigned to room with Jun Marchis Asari in the youth dorms upon joining Esperion, Ohtomo is placed on the B-team after initial assessments. Coaches note his ability to maintain pace with Esperion's junior academy players during practice. Seeing Ashito struggle with fundamentals, Ohtomo secretly joins Ashito’s nighttime training sessions with Tachibana, showing supportive camaraderie. Ohtomo frequently clashes with Asari over differing perspectives on meritocracy. He vehemently defends the worth of players who earned their spots through the entrance exam against Asari’s dismissive attitude toward newcomers. These conflicts escalate into physical confrontations, underscoring Ohtomo’s determination to prove his place. In competitive play, Ohtomo evolves from an anxious participant to a composed midfielder. During Esperion B-team’s debut match against Seikyō High, trailing 0–3, he argues with Asari at halftime. Later, following Ashito’s tactical instruction, he positions himself unmarked in the penalty area, receives a pass, and scores the equalizing goal in their 4–3 comeback victory. Teammates prompt him to reconcile with Asari post-match. Ohtomo remains observant of senior players like Haruhisa Kuribayashi, acknowledging their advanced skills. Off the field, he occasionally displays lighthearted antics, attempting to attract romantic interests by leveraging his Esperion status or spying on Ashito’s interactions with Hana Ichijō. His journey traces a progression from self-doubt to leadership, driven by his passion for football and fueling his resilience and growth within Esperion’s competitive youth system.