Well can't say much about Zeref tbh, it's all guess work really at this point and threres alot to guess but I will say one thing.
The talk before about people joining the FT and what not I honestly never cared for all that, be it every bad guy turned good or no one at all didn't really matter to me who joined FT or not but damn, when Ultear looks that hawt I can't help but want her to join!
Moar Ultear = moar win IMO.
Still interesting to see how things turn out now, I suspect tho we might get to see a dragon or more dragons now which I am really looking forward to.