^Natsu OHKOed Zancrow by combining two attacks Zancrow was immune against. One of which Zancrow was even using for nourishment. This is all so random nothing's really off the table.
I won't say it's impossible, but I still think it's unlikely. With Zancrow, regardless of their abilities it was still basically two fire users fighting. It's not a stretch that Natsu could suddenly control fire better.
But Natsu beating Hades still has some strong implications, one of which would be surpassing the guild leader in the span of no time at all. Where does that leave everyone else? It seems like it would bring about a bunch of changes that would change the dynamic of the story. Could Grey act like Natsu's rival, or Erza as Natsu's superior? At best, I still see a team battle where Natsu probably gets the final blow.
Or Makarov gets healed. I forget, is Wendy out of magic or not? If Natsu is up again I don't see why Wendy can't at least get Makarov into walking-so-I-can-sacrifice-my-life-and-forfil-that-foreshadowing condition.
Something unrelated, but it terms of fights this arc has actually been really good. Grimore's still a credible threat after losing like half their team, surprises are occuring here and their, and these fights have been great. It's a shame the story isn't going as well. But what I really like is Ultear surviving this chapter. I thought she'd lose with Kain here, but her leaving opens the possibility of a new fight that I can't even predict. The others being Erza vs. Lady Sword Midget and Grey vs. Imagination man, but I hope it's really Ultear. Actually I forgot about Wood-plosion man, where is he going to fit into all this?
Yeeeeep….a good arc for mindless fighting.