I have some idea about the key to reawaken zeref.
Hades said he assembeled all keys that are need to reawaken zeref. And in the latest chapter we have noticed that zeref got those crazy zancrow eyes.
Are the keys to reawaken zeref hidden in the 7 kin and their lost magics?
Those lost macigs might be probably the 7 magics of zeref that were sealed away after he was somehow defeated.
And with being confronted to zancrow this acnologia triggered which somehow could be a ability to absorb someones magic and intentions. He was already confronted to Zancrow and Asuma died on the island. Now Hikarua KAin and Rusty Rose (+ Hades?) I think maybe he heeds to kill all those 7 kin to get back his full powers.
That would mean that we could get the future situation that zeref + his guild (tartaros?!?) hunts down the remaining 7 kin. meldy, ultear.... well and probably lucy because she has the power over capricorn which would give our little blonde girl another important role.
So i guess we will know soon. If Zeref kills Kain and Rusty Rose i'll really start to believe my theory.
What do you guys&girls think?
I don't know, but I remember that one of the key were found/built (or similar) in the tower of paradise, at the end Urtear and Hades said something of that kind, laughing about Gérard, so I don't think it's linked with the Seven Kin..
Zeref does not need awakening, he made it painfully clear to the recently deceased hades the whole key thing was but a lie for losers and fanatics. It would be interesting to know what the keys actually were as one of them did seem to order the annihilation of a town.