User blog comment:IamJakuhoRaikoben/Chapter 353: Exorcism, Review./@comment-71.230.108.206-20130927190532

I just thought what if Frosch turns out to be a demon, might not be a regular exceed with it's age stated unknown just like Natsu and Gajeel. Future Rogue also said in a year's time Frosch will be killed meaning it was probably by the hands of a devil slayer or at least something related to these upcoming events.