The Cindervault

A Vallen Imperium bronze-vaulted hall sunk into the Emberthrone's north-west flank, its processional axis aimed at the caldera — sealed from the outside because what still glows in its apse was too dangerous to use.

Black basalt walls scorched orange by a thousand years of the mountain's breath, workings still live and pulsing with something that feels older than the Sundering fault running wide through the apse. The Imperium built it here to read the mountain. Then they read it and sealed the door.