The second area in the Castle Stronghold after the Castle Courtyard, the Dungeon of Torment is a dark and crumbling place. It's not unlike the Forsaken Province's Mausoleum, but where the Mausoleum was a perversion of undead souls, this place is a gory testament to torture and cruelty. An unholy green liquid runs under most of the platforms, which are joined by wooden planks. Thankfully, this is a relatively short area.
There's a Runestone hidden down the first set of stairs, stashed behind a barred gate (which isn't raised until near the end), behind a destructible wall. Another Obelisk waits near the exit to the Tower Armory.