Mayor Ooguro

The town mayor where Atsuko, Yui, and their father have moved to. As a friend of Shinji he's responsible for helping them move, for setting Atsuko up with a job as a teacher, and for their large apartment. They owe him everything.

He encourages Atsuko to volunteer her time with the city.

Spoiler

He has created the town to be a paradise for men where women are property and rape and public sex are encouraged. Volunteering is actually a sexual slavery ring.