User blog comment:Marco the Marine Admiral/Theory: Evilness Can Lead to Power-up for Dragon Slayers/@comment-112.198.79.220-20140628162435/@comment-7418318-20140628182402

The last time we saw Natsu use Dragon Force was in the Nirvana arc. He got a lot stronger since then, so maybe his destructiveness in DF rivals or even outclasses that of Sting by now. Especially if he can go into Dual Elemental Mode and DF at the same time.