Shinpei Izumi commands the Shinkansen Ultra Evolution Institute's East Japan Command Office Ōmiya Branch during the original series. His background includes membership in the six-person Shinkansen Develop Team prior to assuming command at Ōmiya.

Within the Institute's structure, Shinpei reports to superiors like Subaru Azuma, the overall chief commander, and previously answered to Isaburo Yatsushiro and Chikuma Kiyosu. He oversees branch operations and collaborates with colleagues including researcher Hibiki Mishima (who nicknames him "Izuppe"), mechanic Kintoki Odawara, and operators such as Futaba Mihara. He maintains a professional connection with former schoolmate Hokuto Hayasugi, the initial Ōmiya Branch director before his transfer.

After the original series, Shinpei transitions to the Shinkansen Ultra Evolution Institute's General Command Office, promoted to the position of chief commander within the organizational hierarchy.

Shinpei first appears in Episode 01 of the first season and later features in Episode 28 of the second season. He also appears in the film *Shinkansen Henkei Robo Shinkalion the Movie: The Marvelous Fast ALFA-X That Comes From the Future*, fulfilling his institutional role during the ALFA-X prototype events. He has no documented appearances in subsequent series like *Shinkalion Z* or *Shinkalion: Change the World*.