Commander Shinpei Izumi heads the Shinkansen Ultra Evolution Institute's East Japan Command Office Ōmiya Branch. His foundational role in Shinkalion technology development traces back to his position as one of the six original members of the Shinkalion Develop Team.

Within the Institute hierarchy, Shinpei Izumi reports to superiors Isaburo Yatsushiro and Chikuma Kiyosu. He maintains professional ties with Ōmiya Branch colleagues Hibiki Mishima and Kintoki Odawara, alongside a history with Hokuto Hayasugi—first as a schoolmate, later as a fellow Institute member.

During the events of *Shinkansen Henkei Robo Shinkalion: The Marvelous Fast ALFA-X That Comes From the Future*, Shinpei Izumi spearheads the investigation into a mysterious glowing ALFA-X figure within Hokkaido’s Konbu Tunnel. This coincides with renewed assaults by space entities Nahane and Ohanefu, accompanied by their Giant Monstrous Beings. He participates in the Institute’s nationwide counteroffensive, coordinating Shinkalion teams from Hokkaido, Yamagata, Ōmiya, Nagoya, Kyoto, and Moji branches against the extraterrestrial threat.

His duties encompass operational combat command and strategic oversight. Following Hokuto Hayasugi’s disappearance during an attack, the Institute appoints a time-displaced nine-year-old Hokuto as pilot of the advanced Shinkalion ALFA-X prototype. Shinpei Izumi’s responsibilities involve supporting this decision and integrating the ALFA-X into the overarching defense strategy against the invaders.