User blog comment:B214/Talk About What You Want! 2/@comment-24098614-20140828014602/@comment-1359322-20140828015334

It's true that Diehauser allied himsekf with Rizevim because of his family, he said that in Volume 17. As to how it transpired no one knows yet. But it does involve Diehauser's cousin and the exorcist Masaomi.