Skyward Sea

The Skyward Sea is the sea ringing the northern ice cap of the planet. The folks on the northern end of the eastern continent have many legends surrounding the sea. The one that it's name derives from states that the pressure of the moon and sun (said to be light and dark incarnated) presses the water so hard that it forms ice. They believe that the cold in the north of the world is actually a byproduct of the ice, not that the ice is a byproduct of the cold. The belief is that the whole mixture in inherently unstable, and that the cold is the pressed in darkness radiating away from the water, and that the pure white appearance is the light radiating away from the water. When light and dark have sufficiently radiated away, it will go back into just water. 
With this belief set, they are also one of the cultures that supports Light and Dark as true Asti, not imposter Asti like much of the world.