Sanctuaries were the only respite to the corruption of the abyss, and the only gift given by the lords of the material plane, which meant the gods in this land were influenced by the realm of Demons.
And don't think the world of Demons was anything like the hell from the scriptures, the world of the dead and the demon realm differed on one aspect only.
"Demons are fallen humans that were corrupted by a devil." They in a way are undying, no matter how many times you kill the demons, they will be reborn back into the river that flows through the heart of the Abyss. For their lives had been connected to the realm of Demons, they are slaves to the will of the devils that rule over them.
As for who or what the Devil is? Few understood them, but one thing was certain, they are the dark side of the human mind given form. They were born of the hatred and negativity of the beings on the material plane, which is why they hold so much sway over them in return.
