The Procession of Last Breath

You enter a circular temple chamber where the air tastes of cold iron and old incense. A sealed basalt door fills the far wall, its black surface threaded with silver lines and corpse-pale blue fire. Three symbols glow within the ward: a waning moon, a raven with an open beak, and a mound of falling ash. Gray dust drifts upward from a bronze basin, while somewhere behind the door, something knocks three times and then waits.