User blog comment:IamJakuhoRaikoben/Chapter 337: The Golden Plains, Review./@comment-5871436-20130628225515/@comment-1359322-20130629041357

Actually if you analyse this entire arc from the meeting with Zirconis from the Dragon Graveyard, you'll notice that arc is greatly tied to the creation of Dragon Slayers and Acnologia. The 7 Dragons most likely came before the Dragon Civil War. Also if you think about Zirconis (spirit) finals words, "because of you i was", maybe he was referring to the events in this arc. Also how Zirconis got his nickname and the single Dragon that questioned the supremacy of he Dragons might turn out to be Atlas Flame because of his friendship with Natsu.