When you sleep, your soul briefly returns to the place where it was created/goes to when it dies, and seeks nourishment. Everybody's soul is created with a little link (or you could say a greater entity calls it back) to that place so that it can return easily, but upon death, the soul returns via that and annihilates the link as if returns.
Also, as an added thingy, you could say the entity supplying the link, or residue of the links themselves, (whichever) is the source of all arcane power.
When the campfires grow dim, stories are told. Stories of lost cities, great heroes and legends of old. One of these is the story of Knurlheim. Once the proud capital of the Dwarfs, now a ruin- abandoned long ago. Filled with vast riches and treasure. It’s secrets forgotten with the decline of the Dwarfs, long ago. No one knows is certain if it ever exsisted at all.