Valley of Eternal Midnight

In Oelleroth, in the Bellyle Forest, on the western flanks of the Aendril Mountains foothills, lies the Valley of Eternal Midnight. On approach, the valley narrows into a rocky, shaded ravine. The deeper one hikes into the cleft, the higher the walls soar above, and the light grows dimmer because it lies at an angle where direct sunlight never strikes its floor. At the terminus of the valley, where Lorg’s Manor is located, there was once a waterfall, but now it is absolutely dark.
While in the valley, everyone is granted an on-site-only form of true darkness vision. Where the waterfall once was, the castle is built into the canyon’s walls, rising to the ceiling and disappearing into the rocky overhang above. Six black towers defend it, and it has three gates, one located in every even-numbered buttressing wall. These gates are have no doors but are each filled with inky vacuums that even dark-sight cannot pierce.
The keep is in ruin and guarded by Midnight Guardians (see Bestiary). Within the courtyard, the gate is a round portal four yards in diameter that is sealed with a solid granite valve. An ornately gilded Ouroboros ring is mounted at the valve’s center. If the ring is turned counterclockwise, the valve unscrews itself from the port and rolls aside. Beyond lies a circular shaft that leads into the mountain before opening in a large round chamber.
This room is a hub and from it radiates three other identical shafts. One of the shaft bisects with another tunnel, but this new one is vertical, not horizontal. It runs very deep and empties into an underground river. Ten yards above the river, there is an opening in the shaft and a horizontal shaft that leads to the tomb of Lorg.
The crypt houses stone sarcophagus. This is a fake crypt intended to throw off grave robbers. In fact, the sarcophagus is the gate to another set of stairs. Here is a gate to a partial plane called Lorg’s Retreat, where Lorg the Shadow Mage languishes in eternal captivity.