User blog comment:FairyRaven/Fairy Tail Chapter 324: The One Who Closes The Door, Review and Commentary/@comment-112.203.79.12-20130322141156/@comment-1776824-20130322152418

Based on the pieces of info floating around, it is heavily implied that the Shadow never existed in the original timeline, hence the "I don't know this Gajeel", which would indicate that the Shadow is actually Future Rogue, which would negate everything he said about wanting to save the future. Besides, following that logic, the events of the GMG didn't flow the way they're flowing now, in some aspects, at least.