Sleep
All organisms sleep, but only some of them wake up. Sleep is at the very core of reality; it was granted us by the gods. Then, we evolved the ability to sometimes wake up and exist in this place too. But this is all happening inside sleep, and at any moment, we can choose to go back. Sleep is reality. It is where everything comes from. This place is toxic to us; when the toxins have built up, we die, and death will be like sleep. What we call dreams are our memories, interpreted by the brain, of what it was like to sleep.
The things that are the most alive, are those that sleep all the time. We call them “dead”. A rock is alive, because it is divine. Rocks know everything, but we can’t understand them because they are silent. Humans are in-betweenish creatures. The gods can’t touch us directly, because if they did, they would melt into us. We are toxic to them, just as the world is toxic to us.