User blog comment:IamJakuhoRaikoben/Chapter 503: The Last Sight Seen, Review./@comment-7418318-20160928235211/@comment-7418318-20160929140623

@B214: Sure, but then Natsu was unconscious throughout most, if not all of that. And the moment he came out of his restraints, Dimaria would surely have stopped time right away.

Or do you mean that maybe he used God Flames, because unlike all his other magic those weren't affected by the magic sealing stone? I find that very unlikely. Dimaria's god powers were sealed by the same shackles and during the Tartaros arc Natsu wasn't able to use any magic either while sealed, including the Flame God Magic (if he has that).

Thus I think that your theory, while definitely possible, is rather unlikely and Natsu used something new that we didn't encounter yet (from him anyway).

@CNBA: I wouldn't put too much stock in the exact shading. It was a very long time since we saw Zancrow's magic the last time, so Hiro might have felt like a graphical upgrade might be in order... IF it is the same power. I'm not saying that it is, just that after such a long time we can't rely on differences in shading.