User blog comment:Miskos3/Fairy Tail 539: World Destruction, Review/@comment-24053170-20170611084444/@comment-7418318-20170611184919

I'm pretty sure that now that they are inside of Acnologia, the DS will find a way to defeat him from within, which they couldn't have done from the outside.

Thus even though it appeared like Anna and Ichiya's sacrifice was for nothing and made things appear even worse, ultimately it will be this very sacrifice that allowed the DS to beat Acno... unless of course they are alive.