Imai is a member of the Hakone Academy Bicycle Club who impersonated Fukutomi during middle school.
Imai has thick eyebrows similar to Fukutomi's and sparse freckles on his cheeks. He had shorter hair in middle school.
Imai jeopardized Fukutomi's acceptance into Hakone Academy by impersonating him while challenging other cyclists and generally being a menace. Fukutomi's middle school caught wind of this and decided not to give Fukutomi a recommendation to Hakone Academy. Fukutomi and Shinkai went searching for the imposer to clear Fukutomi's name. Imai was shocked and frightened by their sudden appearance and tried to weasel his way out of the situation. He described how others told him he looked and rode somewhat like Fukutomi and how using the name brought him popularity.
Fukutomi called Imai out for his unsportsmanlike behavior and Shinkai asked him to follow them back to their middle school so they could prove that it wasn't Fukutomi behaving badly. Imai responded with an outburst of jealousy directed towards Fukutomi and then took off, ignoring the traffic light. Even though Shinkai and Fukutomi waited for the light to change before following Imai, they still caught up to him easily. Fukutomi gave Imai some friendly advice about how Shinkai takes on a demonic form when he races seriously. Imai appears terrified as Shinkai's face changes, and it can only be assumed that he was soundly defeated.
In high school, Imai is still known for his smooth-talking skills. He appears to have a somewhat managerial role in the team as he is shown talking with a representative from the magazine "Cycling Time." He is also very eager to praise Shinkai and Fukutomi, saying that Shinkai is incredibly fast and Fukutomi is amazing as well.