New GMS exclusive content soon?

Ah, yup, think you're right.

I'm leaning more towards something with Dawnveil. Hell, I would be happy if this was something related to Blackgate City. Ala them cleaning up the area and we can go inside the portal. Though I highly doubt it. If this is Masteria I'm going to lean on the fact this could be Subani, could also be the Dragon Door since it just mysteriously appeared when they redid Masteria after the invasion in the first map. That would be pretty cool.