Ahoy_NATO said:
Maybe you're right, either way, I still don't think the powerup was an asspull. If Mashima wrote MB particles have metal in them then it was specifically designed as a mechanic for Gajeel to utilize. It may seem BS to some people but I personally think that was Magic Barrier particles intended purpose. We'd never heard of them until Tartaros where everyone in the guild was effected besides Gajeel. Now he is using them to gain Dragon Force, something he didn't do last time since he didn't need it to defeat his enemy (Iron Shadow Slayer Mode).
I wrote a whole paragraph why this is not an asspull to avoid dumb claims.
What ticks me off though is the fact that the mode is described as "Jet Black", maybe I just read too much into it and overanalyzed a generic Dragon Force achievement, but it also looks demonlike.
The only characters that have been associated with the color Black are Zeref, his demons, God Slayers, Gods, that thing that possessed Sting, Sting himself, his Dragon and Gray.
My assumption is that the overall message of Fairy Tail is Gods inscribe predetermined fates. While humans forge their own destinity. Hiro Mashima is giving us hints on the endgame through those small details and the endboss isn´t Zeref but the God who cursed him or something beyond that. Which is why i assume that this mode isn´t Dragon force alone, but a form of demon/dragon slayer hybrid.
This would also explain why he was capeable of hitting an intangible demon body.
Simply put Gajeel used fire to fight fire similar to Gray, although I predict that the final solution is to pour water on the fire.