Araki Masatoshi

Tsukasa's childhood friend who works for a small pharmaceutical company. He has been Tsukasa's neighbor since he was very young and always took good care of him. However, when he entered high school, he rarely played with Tsukasa. He then went to a university far away, where he had no interaction with him.

He loves the main character like a younger brother and is willing to do whatever he can to help.