In the default setting of the Fourth Edition, there's a grim dimension only reachable by magic and named the Shadowfell. Almost devoid of living creatures, it teems with all manner of undead, and characters who die end up there before fading away. Fine so far, it's a standard mythical "Land of the Dead". Except that every detail of the ordinary world is mirrored in the Shadowfell. Every ordinary building has a Shadowfell ruin and every port has a silted-up equivalent choked with rotting equivalents of ordinary ships. Obviously Shadowfell is not some magical dimension, but just the future after a disaster that killed everything without doing much large-scale damage. The buildings are ruined not because of mystical corruption, but because they've been sitting around for decades without maint