Nagatoro Naoki

Yuuki's father and Yuriko's husband. He is also Saya's older brother.

He works for major general trading company and spends most of the year on business trips. He is currently on assignment in Europe.

He is a sports-orientated, as is typical of a successful trading company man, and is very strict when it comes to education.

He comes into conflict with Shouko regarding Yuuki who wants to raise him in a carefree manner. This reached its climax when Yuuki drew an illustration of him instead of studying and ended up divorcing Shouko.

He reflected on his actions during the situation and feels guilty about it. He eased up on his criticisms about her.

He remarried Yuriko who was a kouhai from the same company, but he continues to make frequent business trips.