Hayato Ōji, alias Blue Gelato, operates as the soldier of courage in the heroic team Gelato 5. His surname Ōjino contains the word "prince" (王子), mirroring his princely demeanor and status as the team's most handsome member. This appearance fuels his popularity with women, though his tendency to indiscriminately call out to cute girls often results in rejection and physical retaliation like slaps. He fights wielding dual short swords, showcasing a dual-wielding combat style. Despite his heroic role, he displays a competitive nature and overt jealousy when other men, especially teammate Fudo Aikawa (Red Gelato), gain female attention. His personality features persistent flirtatiousness, frequently approaching women with phrases sprinkled with gratuitous English such as "My sweet honey" in the Japanese version.

A recurring narrative element involves his obsessive pursuit of Kiki Majima, ignorant of her secret identity as the Beast Princess of the antagonistic organization Gekko. Their encounters follow a comedic pattern: Hayato attempts to woo her at locations like Shonan Beach or a school festival, only to be consistently knocked unconscious by her. This dynamic extends beyond the main storyline into an epilogue where Hayato joins Gekko, continuing his futile efforts to win her affection in a manner reminiscent of a comedic chase archetype. His background receives minimal exploration, with his actions emphasizing a character defined more by romantic misadventures than personal growth or deeper motivations. His given name "Hayato" combines "falcon" (隼) and "person" (人), while his surname Ōjino means "prince's field" (王子野).