Board Thread:General Discussion/@comment-28189972-20161122011510/@comment-4010415-20161122082002

When Weiss sent cyan beams at the giant Nevermore in volume 1, you can hear her spin the revolver in Myrtenaster before she does it, so I think that was supposed to be an indication that the cyan beams were Dust.

As for the barrier, that's most likely Dust too, and I can't help but wonder if both the beams and barrier are the same Dust, since Weiss only has six colors of Dust in Myrtenaster and there's nothing else that the beams could be from. Maybe the beams and barrier are made of the same substance, just manifested in different shapes and used in different ways, like how Weiss makes ice Dust manifest in different ways - a sheet, crystals coming up from the ground, a giant sword, crystals that she launches at Flynt, etc.

Since the colosseum had the same kind of barrier (invisible until struck, cyan-colored shockwaves radiate from where it's struck), I think it's safe to assume that it's Dust, not Aura... unless the colosseum has some kind of horrific machine that's sucking Aura out of people to make that gigantic barrier dome. But considering that Aura transfer technology is apparently a recent invention, I'm gonna go with assuming the colosseum uses Dust for its barrier.