The Shadowfell

“The shepherds opened the door and told her to look in. She looked in and it was very dark and smoky. From within the darkness she also thought she heard the rumbling sound of fire accompanied by tormented cries. And the smell of brimstone wafted from the door. She turned to the shepherds and asked, ‘What does this mean?’ The shepherds told her, ‘This is a byway to hell, to a land of neverending shadow, and the home of the prince.”

The dark and daemon infested lands lorded over by the Daemon Prince Aloth. The Shadowfell goes by many names, but is normally easily understood what realm is being referred to by it's description.

Vast mountain ranges of rocks sharp enough to carve flesh, deep cavernous cave-cities full of Daemons, their spawn, and those unlucky enough to have been dragged into this realm for their pleasure. The mines of the massive dark cities delve deep into layers of rock, withdrawing ores for use in producing weapons of war. There are no forests, and what bodies of water exist are universally toxic, and inhabited by horrific creatures that are the things of nightmares.

The Shadowfell is divided into regions, each ruled by a Greater Daemon in their own particularly savage way. None have returned alive from here, save for a small number of curious experimenters, who returned quickly to spend the rest of their mortal lives in fear of having to ever return.