User blog comment:IamJakuhoRaikoben/Chapter 433 & 434: Ikusatsunagi & Demolition Fist, Review./@comment-25693405-20150513015631

Lets forget about dragonification. I am an author myself, and the only reason to mention something like that is to clarify it for the reader. That said, I think that the Yakuma-god's strength was tied directly to Arlock's own power. (Similar to how the power of Exodia was tied to it's summoned in the YuGiOh "Dawn of the Duel" arc) If this is true, then Natsu defeating the god makes sense. Otherwise, this fight is BS, unless gods is FT maybe just aren't all they're cracked up to be (which is possible). Maybe dragons are just stronger than gods, who knows. It could have something to do with Zancrow's God Slayer Magic, but I don't think it's that obscure.

As for E.N.D. awakening, I've seen zero evidence for or against this, so I have no opinion, but I'd like to point out that while E.N.D. stands for "Etherious Natsu Dragneel", it's still possible that Natsu is NOT E.N.D.. It's entirely possible that there's an etherious Natsu AND a human one. In effect, what this would mean is that Igneel named the orphan he adopted after the original E.N.D.