TV-Series
Description
Kōtarō Miyao is a classmate and close friend of Haruo Yaguchi throughout their middle school and high school years, characterized by brown hair and blue eyes. He acts as a supportive and observant figure in Haruo's life, frequently offering non-judgmental advice on relationships and personal challenges. Miyao exhibits a protective, brotherly dynamic towards Haruo, deeply caring for his well-being and intervening to mediate conflicts involving him. Academically diligent and socially adept, he enjoys popularity among peers. His perceptive nature allows him to recognize subtle emotional shifts in others, such as Hidaka Koharu's feelings for Haruo and her changing moods.

During middle school, Miyao develops romantic feelings for Ōno Akira but consciously steps back upon recognizing the mutual connection between her and Haruo, suppressing his own feelings to avoid complicating their relationship. He openly declares himself Haruo's closest friend ("mabudachi") and remains a steadfast supporter. When Haruo decides to retake high school entrance exams for Jōran High School, Miyao assists him with studying and provides encouragement. In high school, he continues monitoring the evolving relationships between Haruo, Akira, and Koharu, often acting to prevent or defuse tensions during their interactions. While expressing frustration at Haruo's obliviousness to romantic cues, he consistently supports his friend's decisions.

In adulthood, depicted in the spin-off *Hi Score Girl Dash*, the 28-year-old Miyao works at an advertising agency. He maintains his friendship with Genta Doi, regularly socializing over drinks. Despite his earlier popularity and supportive nature, he remains single and has no documented romantic experiences. His professional life involves navigating various workplace challenges, though specific details about his career progression are not elaborated. Miyao and Doi commiserate over their shared lack of romantic success.

Miyao's family includes unnamed parents, older siblings, and younger siblings, though no further details about them or his home life are provided. His role across all media consistently emphasizes loyalty and emotional stability within his friendships, particularly with Haruo.