Location from acotar-wings-and-ruin by
An ancient subterranean fortress carved into a mountain, holding horrors and beings older than the courts of Prythian.
The Prison is not a place of justice but of containment—a vault for the things the world could not kill and dared not free. It was built before the High Lords, before the Treaty, in an age when the Cauldron's power was raw and the earth still remembered being shaped. The wards that bind it are older than any living fae, and they hum with a constant, bone-deep vibration that warns trespassers: turn back, or be counted among the prisoners.
A jagged black mountain rising from a dead lake, its slopes barren of life, with a single iron door sunk into the rock. Inside, corridors of obsidian stretch into absolute darkness, lit only by faint, cold faerie lights that seem to recoil from the deeper levels. The air is heavy with the smell of damp stone and something older—rust? Blood?—and every step echoes like a judgment.
Also known as: The Prison Under the Mountain, The Sunken Fortress, The Dark Hold, The Mountain of Silence