User blog comment:IamJakuhoRaikoben/Chapter 371: Tartarus Arc: Part 2 - Song of the Heavenly Dragon, Review./@comment-24367018-20140214183118

After getting away from the messy epicness (depending on your POV) one thing stood out for me: When the battle of END is about to be wrapped up; the person who'll defeat him/her/it/whatever, won't be Natsu, Gildarts, one of the remaining Gods of Ishval or any one else of the sort. Zeref'll be the one to save the day. Based off of his chat with Mavis in chapter 340. (It's a flawed guess but whateves)

I did have another thought, but I can't remember it so meh.