User blog comment:Selim 009/Seven Dragons Vs. Seven Dragon Slayers/@comment-5592847-20130428211103/@comment-15382134-20130429071418

What about that dragon that's between Zirconis and the Rock Dragon? It looks like his element is white steel.

I think the only way dragon slayers are able to defeat dragons is by entering Dragon Force. Natsu, Gajeel and Wendy can't enter DF on their free will like Sting and Rogue. So we already know there's a fire dragon (Atlas Flame) and Natsu will probably fight him and enter DF. The dragon Sabertooth are fighting right now is for Gajeel. But unfortunatly, I haven't spotted a wind dragon for Wendy yet...