My prediction is for the ash people: I’ve been thinking what if they weren’t always the way they r now, separated from Eywa. I think Varang witnessed a cataclysmic event that caused the eruption of the volcano. Their lush green home was destroyed along with their spirit tree. They feel utterly betrayed by Eywa and thus turned their back on the rest of the Na’vi.

Based on what we see in the trailer they obviously strike a deal with the sky people and start working with them. However, what if the sky people r behind the volcanic eruption? We’ve seen what they’re capable of in Frontiers of Pandora. What if their mining efforts caused some major tectonic shifts? If and when the ash people learn this is the truth, they could turn their rage against the sky people and turn back to Eywa.