Map of Athel Loren and the Worldroots
The Vaults of Winter is a subterranean network of frigid caverns in the forest of Athel Loren that serves as a prison for many Daemons of Slaanesh.
Due to the compact made between the Wood Elves and the forest, no Elf is allowed to enter the Vaults of Winter. They are connected to the Sínann-Torr, ancient waystones predating the coming of the Wood Elves to Athel Loren.[1a] Within them is eternal winter and caves older than the forest. These caves are filled with many-hued crystals and a visitor who enters is assaulted by visions of their own desires, memories and fears.[1b] The innermost sanctum of the Vaults of Winter is guarded by a Giant made out of stone, as large as a mountain.[1b]
The Vaults of Winter are used to imprison frozen and sealed Daemons of Slaanesh, who always seek to escape, but are usually defeated in these attempts by the watchful armies of the Asrai. When the Winds of Magic grow in strength, the ice breaks and the Daemons launch assaults on the forest. [2a]