In the Time of Dying Stars, countless children warped by the black rain were slain after birth as monsters and hellspawn. A special one lived, to her dismay.
Bringing more fantastic elements to the old classic.
The Great Black Stag of the Southern Forests, Donnerwunsch has drunken deeply of the rivers of the Desert of Divine Despair.
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.