User blog comment:B214/Talk About What You Want! 3/@comment-16281343-20150602164844/@comment-3965848-20150602200220

I think Vol. 20 will reveal  Diehauser connections to Qlippoth and we might have him VS Issei and possibly Riser.

I also think that there's a chance Issei might go JD again if  Diehauser were to do something bad to Ravel and also due to the fact that many kids look up to him and now he kinda betrayed them.

But of course this is just my speculations.