User blog comment:FairyRaven/Fairy Tail Chapter 363: The Stories That Demons Read, Review and Commentary/@comment-1153699-20131207173113/@comment-8153438-20131212124047

I believe among Dragons, there are groups too, with Dragons of the same element.. example, Fire Dragons, with Igneel as their leader/king and Atlas Flame as a subordinate.. About Acnologia, he became the king of all Dragons and his element seems to have a combination of all other elements.. It's something like Etherion, capable of destroying an Island or a Country.. Maybe, after he killed the other dragons, he gained their elements making him more stronger..