User blog comment:Uraharattack/Theories and Predictions, NO FAN FICTIONS/@comment-5303512-20150611042256

Here is a prediction, the main villain of this arc is a misunderstood villain, in his childhood he had a sister and they like Mavis were very fascinated by Fairies and could not stop thinking about them. One day, his sister was killed and which drove him insane. He would do anything he could to find the Fairies. One day he discovered "Lumen Histoire" in Ishgal and so he decided to go and take it.

I think how the entirety of the arc will go, it will start of as an infiltration mission to save Makarov, there will be some battles, the Alvarez Empire have already got the info that they needed, the invasion will begin, massive battles, Fairy Tail must race to protect Lumen Histoire but fail.

Also, I think Lumen Histoire is Mavis Vermillion as a almighty living breathing Fairy with OP powers that is capable of doing anything. A prediction somewhere around the final battle, Alvarez's leader will absorb Lumen Histoire into himself becoming an all powerful Fairy. Only Natsu can stop him and he finally learns of his identity as E.N.D. as is somehow able to call upon it's powers and beat Alvarez's leader with Lumen Histoire.

This actually brings me to a Theory about Zeira, I believe that she is not an Illusion Mavis created or a hallucination but a actual Fairy disguised as Zeira. The reason why only Mavis can see her is because Zeira is shy around others so cast some sort of invisibility Spell to anyone but Mavis. Somewhere at the end of the FT0 series, they will have a moment together and Zeira will gift Mavis with the power of Fairies.