Heh, I have no idea. Dragon Drive was supposedly something that 3rd Generation Dragon Slayers had right? I don't think FT generally makes sense overall - why would Acnologia be afraid of END?

We've also got all the other dragons to worry about, and they all disappeared at around the same time. I'm going to assume that it's not the Dragon Slayers reacting to Acnologia, but rather the dragons inside them that are waking up from that timing.

This means that Sting and Rogue never killed their respective dragons.

Overall this episode sucked ass. Half the time was wasted on everyone's reaction to Acnologia flying over and having the screen shake. Weirdly, some shots of Igneel show pupils and other shots don't.