User blog comment:B214/Volume 17 spoilers./@comment-24589341-20140401062620

I know this is weird, but I'll spill out some of my conclusions regarding Emperor Belial betrayal.

First, What if he did not accept the alliance due to Irina's parants probably killed his loved ones. For example, his lover, wife, siblings, or his children. I don't know, Its just came out from my mind.

Second, Belial must have hid something important in Issei's town (I wonder why the author didn't name it?). Probably Irina's parents took it from its location and destroyed it or hid it somewhere, I think.