Naoyuki is Tomoya's father. Tomoya's mother Atsuko Okazaki died when Tomoya was young, thus leaving only himself to raise Tomoya. After the accident, Naoyuki turns to alcohol and smoking, and held frequent fights with his son. One day while arguing with his son on trivial things, he slammed Tomoya against the wall, dislocating Tomoya's right shoulder. Immediately after that, Tomoya refused to come out of his room, and by the time he finally went to the hospital, it was declared to be untreatable. Ever since then, his father has treated Tomoya more kindly, but like a stranger rather than family. This only hurt Tomoya even more, so he becomes a delinquent, as he is unable to participate in basketball activities any longer, and he avoided returning to his home early enough to be confronted with his father. Tomoya has the intention of running away from his home, as revealed from Kotomi's path.