The Shadow Plane exists as a dark mirror of the normal Material Plane of Faerun. Most physical constructs that exist on the Material Plane also exist on the Shadow Plane, but not all.
Travel on the Shadow Plane is faster than travel on the Material, but infinitely more dangerous.
Our areas cover a section of the normal exterior server areas in a simplified layout. There are no current encounters there presently, but ICly there should be. Basically, one should not go there unless prepared to deal with a number of shadowy dangers. (Actual encounters will be added in the future.)
Unlike PnP, casting Shadow Walk while in the Shadow Plane will not allow you to leave (the spell will fail). You will instead have to find an exit portal.
This area is an OOC construct to allow you to pick an entrance location close to where you actually cast Shadow Walk. Per the spell, you should appear in the Shadow Plane in the same location as you cast the spell. Doing this mechanically involves a lot of scripting, so we instead opted for the simplified Nexus setup.