User blog comment:CNBA3/Chapter 413 Review/@comment-82.236.10.146-20141222190049/@comment-9595671-20141223055919

Agreed, he's gone after things with Zeref's presence.

I have a feeling maybe Zeref is what's stopping him, or atleast its one thing. Remember Acnologia has already been labeled as FT's Bigger Bad, if Zeref's the assumed final boss then Acnologia is the true final boss.