User blog comment:FairyRaven/Fairy Tail Chapter 416: Tartarus Arc: Final Part, Review and Commentary/@comment-77.194.131.213-20150119141826/@comment-5268982-20150119142313

Some of them were still alive but the whole lab was destroyed, so it would take quite a long time to do it. There are numerous explanations one might come up with, but for it to be disregarded and not even be mentioned by the author could be seen as open plot hole by some. And now that you mention it, what about the still alive Demons?

As for the trainings, I hope we won't see them. I want to be surprised when I see the results :P