When night falls, we find peace in the knowledge that daytime will return soon, and vice versa. But what if the world was split: daytime and night are two different, coexistent worlds, each with it's own laws and rules. At dawn and sunset, our soul switches to inhabit our other being, our 'twin'.
The ancient prophet Oijas Bek uttered a cryptic prediction:
In the time of the Floating Ships,
In the Capitol of the Shattered Empire,
The False God will draw the people to his banner,
The Blasphemer shall don robes of righteousness.
No one is sure what he meant, but the various sects each have their theories, which they often fight over.