The father of Hachikuji Mayoi. After he and Hachikuji's mother got divorced, he would not let Hachikuji see her. After Mayoi ran away to see her mother, he searches for her.

Spoiler

In Kabuki, when he finds Koyomi Araragi and Shinobu Oshino outside of his house, he asks if they've seen Hachikuji. It's assumed that Hachikuji is allowed to see her mother after running away in Route X.