The Shadowfell
The Shadowfell, or Svartalfheim, is a dark and largely evil plane of undeath and suffering. Those who draw upon its magic leave some of their souls behind as payment.
In the far outlands of the Shadowfell, the great wolf Fenrir roams. Odin has foreseen that he will come to Midgard and do battle with the gods when Ragnarok comes.