Al the Sloth
I was thinking something to do with emperor, how the wave of energy pushes away from the person, but the more thought I put into it the less likely it seems. I don't think it's a devils fruit though. It seems an odd power though it could be useful. If Dragon is a df user I hope he has a cooler power. I think dance powder makes the most sense.
Dance powder would make a bit of sense, cause he opposes the government so using the Dance powder would be likely.
I still like the thought of a Devil Fruit power though. I can't wait till they unshadow Dragon's abilities and past.