User blog comment:Dispelling Mage/Chapter: Fairy Heart (451) - Review/@comment-5303512-20150908064337/@comment-5303512-20150908105315

Also, another thing I noticed, in his battles with Jackal, Franmalth and Mard Geer, didn't it seem surprising that Natsu seemed to be quick to adapt to them and found their weaknesses?

Ex. Natsu found out how to counter Jackal's touch explosions. Natsu shouting to Lucy and Happy to think of things important to them to prevent their souls from being taken. And Natsu seeing Mard Geer's Thorn Curse for the first time yet manages to dodge them while Mard Geer Mentions that which makes it likely that those who seen his curse for the first time are prone to be hit by it right away.