User blog comment:FairyRaven/Fairy Tail Chapter 401: Igneel vs. Acnologia, Review and Commentary/@comment-5303512-20140922130935

I came up with a wild prediction on how the E.N.D. is going to go down, Natsu will find a way to take the book from Mard. But then E.N.D. begins to speak to Natsu about him opening the book, E.N.D. Would convince Natsu about telling him the truth. Natsu then becomes convinced and opens it only to become possessed.

Classic "Fall of Adam and Eve" scenario.