User blog comment:EvanDude345rv5/Fairy Tail 334 , BOOM HEADSHOT! WTF ?/@comment-203.215.120.188-20130608115841/@comment-7418318-20130608130014

I always got the feeling that the Dragon Slayers can convert their magic to their associated element (considering the creation magic and solid script that's not too farfetched). And the reason why they ate their own element before make a roar is just that the roar uses up a lot of energy.

What's up with Sting eating a metal arrow I don't know either. But then how would he eat "white" or "holy"?

Maybe it was a silver or mercury arrow for some reason. Or since they were fighting a dark mage guild it could have been some magic given shape rather than a real metal arrow.

Or the eating of the arrow was just to show off and had nothing to do with the roar.