So we got even more details from the trailer.

We know the wizard in the castle is actually a Nu Mou as they state in a trailer.

Also the music is the battle theme from the later ARR leveling dungeons (Like Stone Vigil and Aurum Vale) but reorchestrated and it sounds absolutely fantastic. Wasn't expecting that at all but it's totally welcome. Gives me feelings like the Burn did with Penitus being used.