Toshio Koumura  

, 幸村 俊夫

Toshio Koumura was a language teacher at Tomoyas school during his first year. He had once been an energetic individual who enjoyed teaching, but now his age concealed that past. Five years ago, he was known as a strict teacher in an engineering school where he successfully changed the behavior of delinquents for the better. However, at Tomoyas school, his skills were not needed due to its prestigious image. He found Tomoya and Youhei to be unusual individuals and decided to help them improve. Koumura arranged for Tomoya and Youhei to meet, and he retired from teaching one year later before the end of the school segment of the story. In After Story, he returned to organize a fake graduating ceremony intended for Nagisa, which had been planned by Tomoya.