Mest was with the Magic Council all along. The only reason he was in Fairy Tail was to try and figure out was dirt on Fairy Tail so that way the Magic Council would ban them. It would seem that Fairy Tail has no skeletons in the closet per say. Most of Fairy Tail’s members just do the jobs that are requested of them and the live their lives as peacefully as they can. Why in the hell did I get off topic.
The first of the Seven Kin of Purgatory was already on Tenroujima Island. His name is Azuma and it seems that he has a mixture of Magic going on. He can make himself part of the land, has something that looks like magic missiles from Dungeons and Dragons, and he can also cast fire magic. Azuma gets into a rather one-sided fight with Lily and Lily gets his ass handed to him along with Carly, Mest, and Wendy being caught up in the attack. The attack he used was some type of tower of flame. This Azuma also destroyed the Magic Council’s warships that were just arriving at Fairy Tail.
It is also learned that Master Hades of Grimoire Heart was the master of Fairy Tail before Makarov became the master. His name then was Purehito. That flashback showed him to be a nice guy. I wonder what happened to him. I guess one could say that he is the first potential skeleton in the closet for Fairy Tail. The only reason Makarov realized that it was his former Master was because he was using an attack very similar to Fairy Law.