Daisuke Niimi operates as the secondary pitcher for Hodokubo High School's baseball team, backing up the main pitcher, Keiichirō Asano. He steps in to relieve Asano when the starter's performance dips, typically after throwing around 100 pitches. While Niimi lacks Asano's standout pitching prowess, he delivers consistent and dependable performance. His above-average height and long arms grant him a mechanical advantage on the mound, enhancing his pitching leverage through greater reach. Niimi displays a notably calm and composed demeanor during games, maintaining stability even under pressure. This unflappable nature extends off the field, making him a steadying presence within the team. His temperament is marked by patience and resilience, enabling effective performance in high-stakes situations. Within the team structure, Niimi functions as part of the management support system, serving as a senior advisor who works closely with primary management personnel. He approaches his duties with diligence and meticulous organization, consistently prioritizing the team's collective objectives over individual recognition.