Satoshi Arisaka
Harasen's teacher when he was a student. After getting involved with eachother during piano lessons, Arisaka immediately takes maternity leave and runs from his feelings. He taught the highschool twenty years ago during the events of Sora to Hara and becomes a substitute teacher for a short while when Mori-sensei takes absence due to surgery for his hernia. He was once married and hoped to be a good father and husband if he ignored his feelings but he eventually came in terms with his sexuality and got divorced after his wife gave birth. He's not able to see his daughter, but he still gets pictures sent to him by mobile phone which he is grateful for. He is in a complicated relationship with Hibiki and gets into frequent fights with the latter's parents.