Koichirô Iketani leads the Akina SpeedStars, demonstrating dedicated leadership despite not being a top-tier street racer himself. He works alongside Takumi Fujiwara and Itsuki Takeuchi at an Esso gas station in Shibukawa, introducing them to Gunma's street racing scene by bringing them to meet his team at Akina. When the Akagi RedSuns challenge the SpeedStars, Iketani's pride in Akina's racing community motivates him to seek out its fastest driver for defense. This search leads him to tofu shop owner Bunta Fujiwara, rumored to possess exceptional skills in his Toyota AE86 Trueno. Bunta declines to race, citing his age and advising Iketani that skill comes only through persistent practice and road experience. Iketani continues rigorous training. During one practice run, overconfidence causes him to enter an S-curve too quickly; he loses control, collides with a guardrail, suffers minor injuries, and significantly damages his Nissan Silvia K's (S13), preventing his participation against the RedSuns. He then arranges for Bunta to represent the SpeedStars, only discovering that Takumi, not Bunta, is the true driver of the legendary "Eight-Six" who had previously outperformed Keisuke Takahashi. Recognizing Takumi's ability, Iketani allows him to race, marking a pivotal moment in Takumi's career. Personally, Iketani develops a relationship with Mako Sato, a skilled driver from Usui Pass. He misses a critical meeting with her due to heavy traffic and a delayed departure, arriving minutes after she leaves. He deeply regrets this and fails to contact her to apologize. Six months later, they encounter each other unexpectedly at a family memorial service parking lot. During this awkward reunion, both express a desire to talk, leading them to arrange another meeting. Determined not to repeat his mistake, Iketani departs extremely early for their second meeting at the Kamameshi billboard. En route, he encounters an elderly man stranded after missing his tour bus. Despite time constraints, Iketani agrees to drive him to Karuizawa, hoping to return within an hour to meet Mako. Within the SpeedStars, Iketani's driving skills are respected but show limitations during technical sections like Akina's S-curves. He receives advice from Takumi on improving his technique, such as replacing worn rear tires, and practices diligently to refine his control. His commitment to the SpeedStars remains consistent, organizing team activities and mentoring newer members like Itsuki. His interactions reveal a sense of responsibility and occasional social awkwardness, particularly in romantic contexts, yet he demonstrates personal growth through earnest efforts to reconcile with Mako and learn from past regrets.