Split into two groups. The group going south will encounter large groups of Shadows and Virindi. The group going east will encounter large groups of Raven Hand cultists.
Have both groups progress to through the dungeon. Each group will come to a room with several large hostile crystals and a lever. The lever opens the door on the other wing of the dungeon. Pull both levels.
The groups will be re-united at this point. Destroy a group of Slithis. You will come to another large room full of more hostile crystals. Destroy these then one of the destructible doors.
Loot the Title Token: Guardian of the Dark (if there are more than 10 people that want the title, you will need to kill the Guardian again, five minute respawn).
Use the Dark Monolith located on the platform in the center of the room to obtain the hookable version of the Dark Monolith.
Bring the title token to Ulgrim the Unpleasant to be rewarded with the title Guardian of the Dark.
You give Ulgrim the Unpleasant Title Token: Guardian of the Dark.
Ulgrim the Unpleasant tells you, "You found this in the same place you found the Dark Monolith? Here, you should have a new title."