The tower is build upside down into the ground, rather than from the ground up like a regular tower, and is hidden underneath the Library. It can be accessed through a series of secret rooms and passages.
Witches Tower contains several rooms, including a hallway with a portrait gallery of past witches and their familiars. At the very top (or technically bottom), The Committee of Three governs the tower from a circular room whose walls are covered with book shelves. From this room, there is a portal to the Void of No Return.
- When they first see the tower, Frida remarks that most people believe the tower to be located in the Huldrawood. In the graphic novels, a map of Trolberg and surrounding area indeed shows a structure named Witches Tower in the woods outside the city. It never plays a role in any of the stories though.