Doing some research on the #Shadowfell for an upcoming #ElementalApocalypse game, in which the heroes go up against the shadow dragon Morsinth.
The dragon believes that the victory of the Elemental Princes - and their universe-ending lord Tharizdun - is inevitable, and seeks to retreat into the shadows and darkness.
Too bad he captured an angel that the heroes need to get back.
I'm envisioning the dragon's lair straddles the Prime Material Plane and the Shadowfell, with weirdness in between.