User blog comment:FairyRaven/Fairy Tail Chapter 470: Hybrid Theory, Review and Commentary/@comment-1359322-20160125125836/@comment-9595671-20160125131722

We also don't know the limit to Acnologia power is either, I doubt he's gotten any stronger since the Tenrou incident, but we don't know how far apart the Fairy Tail mages were compared to him at the time.

I don't know when we'll see this Black Dragon finally have a challenge against a non-dragon, though the question now is... since Acnologia's finally entered the fray, is this the fight where Fairy Tail has to finish him or will he just come and go again?