User blog comment:IamJakuhoRaikoben/Chapter 334: Sin and Sacrifice, Review./@comment-5201137-20130608072239/@comment-7418318-20130610110251

But with the Dragons we already got that "Friend forced to do evil" stuff covered right in this arc. I doubt Mashima with use that theme again right away.

If it happens I hope Zeref will spirit away the body for now and only deploy the "Demon Gray" much later in the story (after the current arc is resolved).