User blog comment:IamJakuhoRaikoben/Chapter 243: Mistakes and Experiences, Review./@comment-24.215.19.169-20110717173756

I think that Hades vanises all of the people fighting him (Gray, Erza, Lucy, Natsu, and Wendy who already disapeared) and puts them through a test. Since I'm pretty sure that Mashima (I hope thats his name) knows that they can't defeat Hades I think that if they all pass their individual tests Hades will allow them to live because he respects their power and decide to come back when they're stronger. Just a guess.