User blog comment:Miskos3/Fairy Tail 541: The Magic of Hope, Review/@comment-4933386-20170626143821/@comment-7418318-20170627080804

The only things we really know about the Ravines is that they are a weird by-product of the Eclipse and that supposedly stuff trapped within should get erased from existence. And even that doesn't seem to be fully reliable to me, since Anna just pulled those "facts" out of thin air when she shouldn't have been able to know in the first place. Unless she experimented by pushing beings in there... which I doubt she did.

The very fact that by touching it you can be pulled in already shows that the Ravines are different from Fairy Sphere, since that is designed to keep things out rather than pulling them in.

Futher we now see the DS and Acnologia moving around inside the Ravines while time still passes on outside. Sure that could be due to them changing on account of being unter Acno's control now, but I doubt that's the only factor.