Mio Shimazu, a third-year student at Sakaimachi Academy hailing from a well-respected family, carries herself with the poise expected of her lineage. Her long, dark hair frames a demeanor as precise as her adherence to the academy’s standard uniform. Privately, she wrestles with unspoken affection for Takuya Arima, a classmate whose reputation for casual romances clashes with her guarded heart, leaving her emotions suspended between longing and restraint.

Academically, Mio channels her focus into advancing the research legacy of Arima Kozou, dedicating meticulous hours to unraveling the intricacies of Sword Cape. Her tsundere nature manifests in sharply veiled tenderness, oscillating between pointed remarks and fleeting warmth toward Takuya—a tension that weaves depth into her interactions and cements her layered presence within the narrative.