Discovered as a toddler in the Jupiter Mountains by Jun, Jinpei was raised at the Shirayuki Orphanage. Though his early years lack formal records, he asserts lineage from the 18th-generation Iga Ninja clan. Jun, his adoptive sister, later joined him in recruitment by Dr. Nambu for the Science Ninja Team, leveraging Jinpei’s innate agility and latent talent.

As the team’s reconnaissance specialist in the original series, he combines stealth with unconventional tools—American Clackers, Rebound Balls, and Swallow Tops—to execute missions. Despite his mischievous demeanor and petite frame, he assists Jun’s snack bar operations and provides tactical support mid-mission. His playful teasing of Jun over her affection for Ken underscores their sibling-like bond, while he regards Ken as an older brother.

The 1994 OVA redefines his skillset, portraying him as an internet-educated hacker wielding a collapsible cyber-device integrated into his helmet’s interface. His updated civilian wardrobe features a beanie and sweatshirt, while his Bird Style uniform adopts red-and-yellow accents paired with a purple cape.

Concept art from the cancelled Imagi film proposed varied designs, experimenting with gold-and-red uniforms and casual wear incorporating goggles or sunglasses. The 2013 live-action adaptation assigns him the role of a “Receptor” opposing Galactor, though narrative specifics remain sparse.

Consistently depicted as the team’s youngest member, Jinpei relies on inventive weaponry and technology across iterations. His dynamic with Jun remains central, while Western adaptations like *Battle of the Planets* radically reinterpret him as Keyop—a genetically altered figure with a speech impediment—diverging from Japanese-original portrayals.