Hiro Kurusu sports wavy medium-length light-brown hair swept right and brown eyes, with two earrings adorning her right ear. She trimmed her initially long nails for koto practice. Her Tokise High School uniform features seasonal variations: a light blue summer blouse or a white blouse with beige vest and checkered brown skirt in winter, always accented by a red-orange striped bow tie, blue socks, and brown shoes. She seldom wears the school jacket outside performances. A junior high trauma shaped Hiro's worldview when a female transferee manipulated her friends and boyfriend into abandoning her. Convinced human bonds were fragile, she began infiltrating friend groups to sabotage them through lies. Witnessing the Tokise Koto Club's cohesion, she targeted them to replicate this destructive cycle. Feigning enthusiasm to join the club, Hiro strategically sowed discord by exposing Satowa Hozuki's concealed disownment. She framed it as proof of Satowa's insincerity and implied the club was merely her "temporary haven," expecting this revelation to shatter their trust. Instead, the members' unwavering support—especially Takezo Kurata’s immediate gratitude for Satowa’s honesty—contradicted Hiro’s beliefs. Overwhelmed, she fled before tearfully confessing her sabotage intentions to Kurata. Faced with the club’s resilience, Hiro acknowledged her actions stemmed from envy of their genuine bonds and self-loathing over her past betrayal. Seeking atonement, she personally apologized to previous victims, enduring physical retaliation without resistance. Chika Kudo’s blunt encouragement helped her overcome hesitation to re-enter the clubroom, where first-year members welcomed her warmly. As vice-president, Hiro became a protective, emotionally supportive figure. She assisted Kota Mizuhara with rhythm refinement during practice and blamed herself when he vanished at a training camp. She consistently prioritized club morale, once advocating against a member's presence due to collective discomfort. Mutual romantic affection developed between her and Takezo Kurata, though neither confessed openly. Their chemistry featured Hiro’s visible blushes and Kurata’s quiet support, like promising to listen if she shared her burdens. Initially possessing rudimentary koto skills learned from her grandmother, Hiro’s commitment deepened alongside club loyalty. She transitioned from indifference to dedicated practice, aligning her efforts with the club’s national competition goals. Her passion for the instrument fused with appreciation for the ensemble’s collective spirit.