Shin Hyūga is a first-year student at Kawagoe Academy and a member of the boys' choir club. He forms one half of an identical twin pair alongside his brother Kou Hyūga. Both twins are top tenors in the choir, sharing a frenetic energy and outspoken nature that often leads to intense arguments, bewildering onlookers. Despite their tendency to bicker relentlessly, Shin and Kou exhibit remarkable unison and harmonious coordination during choir performances, especially when synchronized with the group's rhythm. Fellow choir member Tenshi Dei observes that Shin possesses a deeper vocal resonance compared to Kou's higher-pitched voice.