I'm working on a game world where light (Lux) gives literal definition to all matter. Anything in complete shadow (Umbra) is without definition and completely amorphous.
At the center of the world, hovering a couple thousand feet above ground, is a glowing ball that emits light and all definition and life in the world exists where the light touches.
Since this is meant for an RPG style game, I want to make it easy for players to adjust to the world. (Everyone knows what a dragon is, even if there are different flavors of dragon in different worlds, for example)
So the question is this:
How should I handle sleep? I've thought about making the light source slowly pulse, and in the darker periods there's still enough light that existence doesn't melt, but people can sleep/skulk/etc.
The world is a flat disk. Lux (the main light source) hovers above it at the axis of the world. Directly below Lux everything is frozen and unchanging because the power of Lux is so strong. The further away from the it you get, the more malleable reality is. So at the edge of the world is a ring of water. Beyond the ring of ocean it fades into Umbra and amorphousness.