DIT 4: "Iron Menagerie"

The Thayans clearly have a multitude of demons, elementals, and other creatures they have captured in the Doomvault. You have even managed to make a couple of allies by freeing them.

Having defeated the Naga that was imprisoning the young Dragon Turtle you freed and finding her treasure stash in the tunnel connecting the two pools in her lair. Unfortunately, the commoners that had become enthralled by the Naga were unsavable as their minds were too far gone and they continued to attack you even after their captor had been slain.

Takin a short rest to catch your breath and take a quick inventory of treasures and any other magical assets within your bags of holding, you head through the southwest door of the chamber where you find a Black Gate, which you intend to use to get to the Gatehouse where you can safely take a needed rest.

But before you can do that you must first defeat the scrags guarding it.