User blog comment:Ash9876/Ashy's Reviews - Fairy Tail Chapter 470, Hybrid Theory/@comment-5914413-20160127142208/@comment-5914413-20160128000639

Didn't atlas do the closest to bowing so far from what we saw of him in the GMG?

Then again, how does one become a dragon king and why are there only two kings so far are also things that might be interesting to look at. If the strongest dragon of their element becomes the king, it would fit more barbaric tribe where the right of the strongest rules, but also show that only igneel and acnologia are strong enough to be kings from the ones shown so far.

If it is however through some kind of tournament, that could explain why there are only two kings so far since those are the only winners revealed at the moment.