as far as I remember Natsu didn't use 2nd origin against Sting and Rouge. he was in his normal mode.
about the question:
he already land a good hit on Gildarts on Tenroujima before they disappeared, he could still do that much, but he would most probably still lose. Gildarts always holding back in his fights because his magic is too powerful and deadly.
about the question:
he already land a good hit on Gildarts on Tenroujima before they disappeared, he could still do that much, but he would most probably still lose. Gildarts always holding back in his fights because his magic is too powerful and deadly.