The Moaning Lands of the Dead and Dying. Many foul creatures of undeath roam here and seek living flesh, no one is quite sure what happened to this large desert island. Maybe you could unlock the mystery and free the tormented.
A mystic ruin that is well guarded by the family of Dro’Hizzir a great upper class of Shadow Warriors. This is unknown to everyone except for Dro’Hizzir. Knowledge that is only passed down from his forefathers and ancestors alike. Well underground in the city of Pulca. The entrance is found in Dro’Hizzir’s office in his ancestorial vault (that has riches in it as well). In the back of his vault is a narrow tunnel way big enough to fit a normal man in that leads to a ruin of his dead Ancestors and riches of the deceased.
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.