Gin Itsutsubashi is an 11-year-old Shinkalion driver from Yamaguchi Prefecture, assigned to the West Japan Command Office Kyoto Branch where he pilots the Shinkalion 700 Hikari Railstar. He shares an exceptionally close bond with his twin brother, Jō Itsutsubashi, also a driver; their personalities and behavior are nearly indistinguishable, with few individual quirks. Both twins exhibit deep enthusiasm for fish, capable of discerning wild-caught from farm-raised varieties and expressing a strong preference for the former. Discussions about fish, especially concerning meals, can trigger notable passion in them.

In combat, Gin favors improvised tactics. This approach, combined with his fervent opinions on fish, initially creates friction with teammate Takatora Kirishima, preventing the successful formation of the Shinkalion Trinity combination. Resolution comes through Hayato Hayasugi's intervention, reconciling the trio. Post-reconciliation, Gin collaborates more effectively with Takatora, actively assisting him in sourcing fish for cooking.

Gin participates in operations alongside drivers from the Hokkaido, Yamagata, Ōmiya, Nagoya, Kyoto, and Moji branches during significant events, including the appearance of new enemies and the deployment of the Shinkalion ALFA-X.