After the encounter with the ghosts the party explored the Proving Grounds. They found one stone altar that appeared to have been recently moved. Sliding it aside, they found some loose tiles underneath. Hidden under the tiles they recovered some gold and gems.
They continued to explore the area and found a large pit in the center which they surmised is where the dragon guardian would come. They also discovered a few of the runic circles on which they would need to place the four artifacts once they were recovered.
Eventually they headed west and found a chamber of horrors. They stood on a stone platform that rose above a massive pool of dark blood. Several other platforms also stood throughout the room as well as a stone walkway traversing the center. At the far side of the chamber the party could make out the hilt and blade of a dagger resting on two separate platforms. At each end of the chamber huge stone minotaur statues stood with massive barbed whips in their hands.
The party headed into the chamber to recover the artifacts and found themselves in one of their most difficult fights yet. They overcame the stone sentinels and their barbed whips, evil demons lurking under the blood, and the poisonous blood itself and emerged from the chamber with the two items exhausted and ready to collapse.