User blog comment:IamJakuhoRaikoben/Chapter 353: Exorcism, Review./@comment-201.124.15.103-20130928060330

I'll put money on Silver being somehow related to Gray. Maybe not his father since his parents were supposedly killed by Deliora but maybe something else. Or heck, maybe Gray's village got fucked by Deliora and Silver who retconningly survived, decided to learn Demon-Slaying magic to take vengeance. Something like that.

Demon-slayer sounds cool, just hoping it doesn't turn out as "great" as God-Slayers (which in this case means completely lame)