Shinji Oda is a 10-year-old student at CySonic Academy, sporting blue-black hair and blue eyes that match his typical elementary school appearance. His personality brims with energetic curiosity and a mischievous streak, often leading him into trouble. Academically, he struggles with his studies and initially knows nothing about Megalo City's history, including the destruction of old Tokyo and its reconstruction.

He harbors feelings for his classmate Molly Rangwald, though he expresses them through bullying behavior. In contrast, he openly idolizes the Borgman warrior Ryō Hibiki, admiring him with deep respect.

A pivotal moment occurs when Shinji uncovers the secret identities of the Borgman team—Ryō, Chuck, and Anise—becoming the first academy student to learn they are Megalo City's cyborg protectors.

Driven by an ambition to become an astronaut, he pursues this dream after the television series' events by actively undertaking astronaut training.