Kazuya Takahashi is a male teenager who appears in the anime Piano. He has black hair cut to approximately ear length and yellow eyes. Known as a handsome student at Miu Nomura's school, he is in his third year and is characterized as athletic, smart, and hardworking. His motivation is focused on his future, as he studies diligently with the goal of gaining admission to a good high school.

Within the story, Kazuya serves as the object of Miu Nomura's secret crush. Miu's shy personality prevents her from expressing her feelings toward him. He is portrayed as a serene presence in Miu's life, and her uncontrolled emotions regarding him become a contributing factor to the internal struggles that hinder her musical talents. The character faces a moral dilemma as he works to balance his dedication to his studies and school life with the possibilities of his love life. Beyond his academic dedication, Kazuya does not demonstrate any special abilities or notable skills outside of those typical for an athletic and intelligent student.