User blog comment:LastationLover5000/Fairy Tail 324 - In Which I AM SO CONFUSED, MAKE SOME SENSE ALREADY (The One That Closed The Gates)/@comment-5918713-20130322230753

I was thinking: one way to use Eclipse is to travel through time; the dragons "doesn't exist anymore", only in a past time = Open Eclipse is the same as bringing the dragons of the past to present = Rogue is evil or a future Minerva said to him to active it to destroy Fairy Tail and all the other guilds to finish her frustration after losing to FT.

Just a speculation.