(see Tome of Magic page 171)
The Heart of the Tenebrous Cabal is the Bleak Academy. It is located on the Material Plane, beneath the Granite Mountains. The Cabal makes the most important decisions there and trains future shadow magicians. Though it is a very large school, the Bleak Academy remains well hidden.
The Academy lies within the heart of the Granite Mountain range, its entrance marked by huge statues flanking a pair of black doors. The entry is carved with glyphs and other protective magic. Inside is a warren of halls and rooms, built in very dwarven style. The Academy has four major regions. The Dormitories, which house the students and can hold one hundred apprentices comfortably. Classrooms are adjacent to the dorms, with the Professors' apartments flanking them. The Parliamentary Hall is the last of the regions. This is where the heads of the school convene. It is like a great colliseum, with row seating all around and facing a Speaker's Platform at the bottom.
The Bleak Academy was once a dwarven outpost whose population fell to mindflayers. After it had been abandoned for hundreds of years, the cabal cleansed the place of all squatters and assumed control.