User blog comment:Omega natsu2/Fairy Tail Zero: Dances with Blades, Review./@comment-24951162-20141023165901/@comment-24039250-20141024005444

I can see Fairy Tail Zero and Ice Trail as a part of a flashback Arc. FT Zero could be Mavis reflecting on her past up to how she died, while Gray's could just be a filler arc showing how he joined Fairy Tail.