User blog comment:Miskos3/Fairy Tail 539: World Destruction, Review/@comment-31560299-20170616091055/@comment-4933386-20170616140926

It could be possible though, but In the Tenrou arc against Acnologia, 3 Dragon Slayers couldn't defeat Acnologia (not including Laxus cause he didnt use Dragon slaying magic) and it was evident that during Grand Magic games, they couldnt even defeat a single dragon on their own. Acnologia being the strongest (definitely stronger now than ever), the dragon slayers will probably still struggle.

To be honest, i expected that Natsu gained power-up from Atlas Flame during that time, but they didn't. Only achieved Dragon King from his training...

But Acnologia's new goal is destroy the entire world I'm pretty sure, but he wanted to get rid of his only threat first; AKA Dragon Slayers. Lol tbh, I'd suck each of them individually so can kill them all off one by one if I was him.