Thermal Tides of the Bedrock Void

Descending into the echoing expanse of the Bedrock Void, Oren keeps a low profile against the slick stone walls. The absolute darkness presses in from all sides, broken only by the dim, erratic glimmer of distant phosphorescent moss far below. Without warning, the biting chill of the cavern air gives way to an unnatural, sluggish humidity.

Reaching out to steady his footing against a jutting basalt rib, Oren's gloved hand comes away damp and stained with a dark, oily residue—the telltale condensation of the high-pressure arcane backdraft filtering down through hairline fractures in the stone from the master control valve above.

A short distance away, across the fractured stone divide, Bram kneels in the cramped confines of the secondary maintenance shaft, attempting to lever away a heavy slab of fallen masonry. His hand brushes against an old brass geophone housing half-buried in the silt.

The heavy instrument vibrates audibly, its internal mercury needle swinging violently as subterranean heat pulses upward through the newly exposed fissure, warning of the mounting atmospheric pressure that threatens to breach the deep conduits entirely.