The Ward of the Unfailing Second

The chamber is a cold, semicircular vault of polished obsidian. A massive, ceiling-high hourglass made of tempered glass stands at the center, its sand frozen mid-fall in a suspended golden cascade. Along the far wall, a heavy mithral door is etched with glowing sapphire runes that cast a rhythmic, pulsing light across the floor. The air is deathly still, yet a faint, rhythmic thrumming like a slow heartbeat vibrates through the soles of your boots. The scent of ozone and ancient metal hangs heavy, and the reflections on the walls seem to lag slightly behind your movements.