Kousei Arima  

Friend A, Human Metronome, 有馬 公生

Kosei is an exceptionally talented pianist who won the Saki Competition at a very young age. However, following the loss of his mother, he stopped playing the piano and was unable to hear the sounds produced by his own hands. For two years, he experienced the world in shades of gray until he encountered Kaori Miyazono, a stunning musician who encouraged him to rediscover his passion for music and play again.