The Shadow Forge is another unique instance of Quelmar's Mysterious Architecture, a strange place that never seems to exist in the same place twice, and exists between dimensions.
About
The Shadow Forge appears to pump and channel energies from The Shadowfell. The forge itself also seems to be a semi-sentient force, as when under attack, it appears to coelesce these shadow energies into umbral creatures intent on fighting off the assault.
Accessing the Shadow Forge was nearly impossible for mortal creatures, and required a special type of key, a chronal key that opened rifts in space and time to access the exact locations of places that seem to float across existence.
History
In 825 PR, the Shadow Forge was shut down on orders of the mysterious archfey known as The Curator.