West Marches: Westmoor
There is a demonic temple under Amber Heath. There are two ways to enter the template. First you can jump into the well and swim over to the entrance. But you will have to unequip in order to swim and there are monsters in the water. But this is the quickest route. The second option would be to go through one of the houses, the only boarded up house in the on the right side of the loop opposite side from the well. In the backroom there is a trap door that will gain you entrance into a underground tunnel. This tunnel will lead you to an outlook in the well. you will need to anchor some rope, slide down and swing over to the temple.
The upper floor contains a totrture room, a trapped hallway, and the Mouth of Dranzilthl; which is similar to what the adventurers discovered in the goblin palace
So far only Sid Maxwell, Garrett Falstad and Throkgar have braved the caves. They encountered a horde of demons that spewed poison gas. But during there combat Garrett Falstad spoke in a demonic language and the temple reacted. Flames start in the statues around him. Then he demanded to be shown the way to an actual challenge and a path was lit for them. They did not adventure very deep though so there are still mystery to solve.
Further down into the demon temple the adventurers found the caverns to be flooded. They braved the water and encountered a giant anaconda, which had made the temple it’s home.
Further beneath the temple is a system of caves, populated by magic oozes and storing the resting place of a great, virtuous, elven hero.