Katsuki Touma

"It's been a while Sayu. I'm the one in charge of this place now, if you have any questions feel free to ask."

He knows that his father and the protagonist's father had a succession battle about who would take over the Haruki Shrine, but he thinks that it has nothing to do with him so he holds no ill will towards Sayu and they get along well.
He helps support her with her part time job.
His job is to support the artificial god Ren and help purify the 'impurities' that were also created when the artificial gods were.
He thinks of Ren as a troublesome little brother rather than revering him as a god.
He's the one who knows all the secrets of the artificial god program and the Katsuki family.