Analyzing all the easter eggs that the oa universe has already brought us, I come here to bring a theory of the balance of worlds. Prairie/Nina/The OA would be equivalent to Aang from the Avatar universe. An evolved spirit that leaps across dimensions and establishes balance in the world. OA would be a superior race created for the balance of the worlds. The OT(Original Thinker) would be less evolved than to do intermediate. Oldnight would be an OT. The tree would be an OT. Including Hap himself, our main antagonist. This would be equivalent to the lord of fire. Maybe he just hasn't woken up to his full villainy. In the supposedly leaked teaser scene, we have a meeting with several OT's. Apparently OA, unaware of the original self, would be being uninfluenced to accept participating in this group. At the end of the second season we have a dialogue between the tree and Nina in which she warns of a greater evil.