User blog comment:Miskos3/Fairy Tail 527: Emotion, Review/@comment-130.105.140.184-20170321124514/@comment-7418318-20170321134032

I'm not sure if it serves any purpose at all. It was probably just an ominous and cool sounding name for a prophecy or somesuch.

Wait... I haven't thought of the Dragon King Festival in ages... but now that you mention it.

When the term was originally coined, it was said it was going to be a fight between Humans, Dragons and Demons.

With Larcade being revealed to be a Demon from a Book of Zeref, that means the current arc qualifies for that. We have lots of Humans, we have Larcade and E.N.D. Demons (maybe toss in Mirajane and Gray in the group too) and there are/were Arcnologia and Irene actual Dragons as well as several Dragon Slayers.