The main character of the series. He is the older cousin of Elis as well as her current guardian. At the time of the series, he is an adviser to the art club as well as an art teacher in training but he used to be an artistic prodigy when he was in high school. During high school, he was good friends with Kiri and Yanagi. When Kiri confessed that she liked him, Hiroki turned her down even though he had feelings for her. It is believed he did this because he knew that Yanagi also liked Kiri so he didn't want to get in the way of his friend's feelings. However, Yanagi didn't know of Hiroki's good intentions and stole Hiroki's composition of Kiri for a national art contest. This destroyed their relationship and left Hiroki alone and heartbroken since he had also turned down Kiri. Since then, he has taken in Elis into his home as her legal guardian.