A city of dark and twisted Derro located beneath the surface of Cassomir.
In Chapter 166, the party learned that there was a secret entrance to the city located inside Miacknian Mun‘s house, and in Chapter 167 they found it in the sub-basement of the site.
In Chapter 168, Dabwick sealed up the entrance with a Wall of Stone.
First Reference: Chapter 62
Other Notable References: Chapter 160, Chapter 166, Chapter 167, Chapter 168