Hayato Oji is Blue Gelato, the "soldier of courage," within the heroic Gelato 5 organization, his codename reflecting their ice cream motif. Possessing notably handsome features, he enjoys popularity among women. However, this contrasts sharply with his persistent habit of flirting with any attractive woman he meets, which consistently results in immediate rejection and physical reprimands like slaps.

In combat against the evil Gekko organization, he dual-wields short swords, relying on speed and agility. Despite his heroic role, missions are frequently sidetracked by his pursuit of romantic interests. This is especially true with Kiki Majima, Gekko's Beast Princess. Every encounter prompts Hayato to attempt wooing her, only to be swiftly knocked unconscious. This dynamic extends beyond the main series into the epilogue, where Hayato joins Gekko's heroic faction but continues his futile pursuit of Kiki, creating a comedic chase reminiscent of classic cartoons.

Beyond his flirtatious exterior, Hayato exhibits jealousy when other men receive female attention, revealing a competitive streak. His speech often incorporates gratuitous English phrases like "What?" or terms of endearment such as "My sweet honey," even in the original Japanese.

His surname "Ōjino" (王子野) includes the character for "prince" (王子), aligning with his perceived princely demeanor, while his given name "Hayato" (隼人) translates to "falcon person," suggesting speed or keenness. His narrative function centers on providing lighthearted moments through his failed romantic endeavors.