User blog comment:FairyRaven/Fairy Tail Chapter 423: Do It All for Love, Review and Commentary/@comment-24039250-20150309235455/@comment-7418318-20150312193459

Natsu demolished a whole horde of them just by charging through them to get to Chelia. And then he blasted out a roar that was big enough to envelope an entire building without even trying hard.

And Lucy? She made a determined attack that took out a single monster. I'm not saying that this is the full extent of her power (far from it I'd expect), but by all the love and admiration I have for Lucy there's no way she could be anywhere near Natsu's current level with anything short of summoning the Celestial Spirit King and we know the price for that.