User blog comment:B214/Light Novel Volume 16 spoilers/@comment-1392308-20131019074749/@comment-1359322-20131019075151

It's not Gasper that is connected with Issei, it's Balor, the God inside the Forbidden Balor View, that is connected to Issei, as to how they're connected, i don't know.

Well Issei is pretty much useless without the Boosted Gear, so he'll need to learn new methods of fighting.