Hiromi Hamaguri, a 16-year-old Osaka high schooler, channels her tomboyish persona—forged by two older brothers—into a fiercely competitive spirit, though she privately yearns to explore cute, girly aesthetics. This inner conflict clashed with her "cool" reputation, especially among hometown admirers, until a junior schoolmate’s offhand "cute" remark spurred her to audition for a national idol program. As the Kansai region’s dance specialist in its seventh season, she formed Splasoda°, a subunit with three fellow dancers. Initial clashes over choreography dominance led Hiromi to recalibrate her approach; she apologized, embraced collaboration, and bonded the group through shared enthusiasm for fizzy drinks. Though their high-octane "Sparkrash" performance missed vote thresholds, viral prank videos salvaged their advancement, underscoring Hiromi’s tactical flexibility.

Promoted to leader of the nine-member 9-tie, she mediated tensions during crises like the second round’s elimination vote, rallying the group to reject solo cuts and negotiate a collective return after a staged withdrawal. Her empathy surfaced in quiet moments—reassuring Suzune Miyama about a surgery scar or nudging Rena Hananoi to flaunt her quirks. Privately, she juggled her gritty image with clandestine experiments in frilly fashion, mirroring her broader struggle to reconcile toughness with vulnerability.

Behind her assertive exterior lay a comedy enthusiast who scouted rising stand-up talent, infusing 9-tie’s dynamic with humor. Post-victory, she prioritized group cohesion over solo acclaim, steering their finale toward a teamwork-centric triumph. Rooted in a name meaning "wide sea" and "beach chestnut," her broad-minded yet earthy demeanor reflects her family’s influence—brothers who honed her protective edge—and her evolution from a conflicted teen to a leader uniting contrasts.