The cathode-ray tube monitor hissed, bathing the cramped cockpit in a sickly, phosphor-green light.

  I didn't blink. I couldn't. I was staring at the massive, pulsing crimson bloom dominating the lower quadrant of the geophone's display grid. My mind, trained in the rigorous logic of Imperial engineering, immediately began calculating the raw physics of the anomaly.

  Frequency: 0.16 Hertz. One pulse every six seconds. Amplitude: Severe. Micro-fractures forming in the surrounding bedrock with every cycle.

  I ran the mass-displacement formula in my head. To generate a localized seismic event of this magnitude without tectonic plate friction, the source object had to possess an incomprehensible mass. Not a hundred tons. Not a thousand. Eight thousand tons. Minimum.

  "That's not a biological entity," I whispered, the words tasting like ash in my mouth. "That's a geological event with a pulse."

  The CRT screen flickered violently. A wave of static washed over the green grid, the scanline warping and bending. It wasn't just a physical mass. The entity was projecting a passive, massive bio-electric field that was actively scrambling the Centurion's low-grade mana crystals.

  I watched the red bloom. It had been stable. Dormant. Then, the numbers on my makeshift refresh counter changed.

  Interval: 5.8 seconds.

  The red mass on the screen shivered. It wasn't a glitch. The edge of the crimson blob expanded upward by a fraction of a millimeter on the grid. It was rising.

  Interval: 5.4 seconds.

  Cold sweat broke across my neck. Why was it waking up? What was the variable? I felt a vibration through the soles of my boots. Not from the abyss, but from the cavern outside the cockpit. Thump. Thump. Kael and the labor crew, working the massive leather bellows. Hiss. The roar of the blast furnace consuming oxygen. Clang. Rax dropping a heavy steel mold onto the stone floor.

  Action and reaction. The Abyssal Digs was a giant stone funnel. We were sitting at the top, banging on the pipes. The acoustic vibrations and thermal shock of our primitive industrial revolution were traveling straight down the granite walls, echoing into the toxic depths.

  We were ringing the dinner bell.

  Interval: 4.9 seconds.

  I didn't power down the console. I didn't even grab my wrench. I hit the emergency hatch release and threw myself out of the cockpit.

  I hit the stone floor rolling and sprinted toward the forge. "KILL IT!" I roared, my voice tearing my throat.

  Rax spun around, his hand instinctively dropping to his pistol. Kael froze, his hands still gripping the heavy iron handle of the bellows.

  I didn't wait for them to process the command. I lunged at Kael, hitting him with my shoulder and knocking the mutated laborer away from the air intake. I grabbed the heavy, cast-iron emergency damper hanging above the crucible and slammed it down over the primary oxygen vent with all my body weight.

  CLANG.

  The oxygen supply was instantly choked off. The blinding white fire inside the furnace suffocated, collapsing back into a sullen, smoking red ember in less than three seconds. I spun around, grabbed a heavy iron pry bar, and jammed it into the gears of the water-powered cooling pump. The cast-iron teeth ground against the bar and snapped, freezing the machinery with a horrific screech.

  Stolen content warning: this tale belongs on Royal Road. Report any occurrences elsewhere.

  Then, total silence.

  The roar of the fire was gone. The clatter of the molds was gone. The cavern fell into a suffocating, absolute stillness, broken only by the sound of my ragged breathing and the distant, echoing drip of condensation from the ceiling.

  "Kid," Rax whispered, his hand still on his gun, his eyes scanning the dark corners of the cavern. "What the hell did you just do? We were mid-cast."

  "Silence," I hissed, raising a hand. I pointed a trembling finger down at the yawning, black shaft that dropped into the mustard-yellow clouds miles below us. "We woke it up."

  Amelia stepped forward, her face pale. She didn't ask what it was. She could read the absolute terror in my posture.

  "I need parameters," I said, my voice barely a thread of sound. "I can't calculate a defense if I don't know the threat's dimensions. Or its depth."

  I moved frantically, but silently. I grabbed a spool of high-tensile braided steel mining cable from the scavenged supplies. I tied the end around a heavy, fifty-pound cast-iron ingot we had just cooled. To the ingot, I lashed a raw, glowing luminescent mana-crystal, and positioned a thick, glass optical lens from a broken Imperial spyglass over it, creating a crude, focused beam of light.

  "A drop-camera," Rax realized, immediately understanding the engineering. He stepped forward to help me mount the spool onto a silent, hand-cranked winch near the edge of the precipice.

  We didn't speak. We released the winch lock. The heavy iron ingot plummeted into the dark, pulling the steel cable with a soft, continuous whir.

  I ran back to the Centurion, pulling the long cable of a portable optical receiver with me, and plugged it into the secondary channel of the CRT monitor.

  "Feed is live," I whispered over the comms piece I tossed to Rax.

  On the screen, a small, grainy circle of light cut through the absolute darkness. The depth counter attached to the winch spun rapidly. 1000 meters. 2000 meters. 3000 meters.

  The probe hit the toxic gas layer. The light refracted violently against the thick, mustard-yellow clouds, reducing visibility to a few dozen meters. The screen was a swirling mess of sickly yellow fog.

  4000 meters.

  "Nothing," Rax whispered over the comms. "Just soup."

  "Wait," I adjusted the contrast dial.

  The yellow fog parted. The probe hadn't hit the bottom of the cavern. It had hit a surface.

  The light from the crystal reflected off something solid. It was black. Not a matte, dead black, but an iridescent, metallic obsidian that seemed to absorb the light and bend it. As the probe descended another ten meters, the scale of the object became horrifyingly clear.

  It wasn't the ground. It was a single scale. Just one hexagonal, armored plate, covered in deep, ancient scars that looked like they had been carved by glaciers. The single scale filled the entire field of view. It was larger than the Centurion.

  Then, the surface moved.

  It was a slow, agonizingly massive heave. The beast was taking a breath. The displacement of the gas was catastrophic. Even at four thousand meters up, the localized change in atmospheric pressure created a violent, upward hydro-dynamic current.

  On the screen, the yellow fog rushed upward like a reversed waterfall. The fifty-pound iron ingot was tossed like a leaf in a hurricane.

  Up on the ledge, the heavy steel winch screamed in protest. "It's catching!" Rax yelled, diving away from the machinery.

  SNAP.

  The braided steel cable, capable of lifting a locomotive, parted with a sound like a cannon shot. The severed end whipped back, slicing an inch-deep gouge into the solid granite wall.

  In the cockpit, the CRT monitor instantly went to dead static.

  I sat in the dark, the white noise of the dead screen hissing in my ears. I looked at the primary radar feed. The red bloom had stopped rising. Interval: 6.0 seconds.

  It had gone back to sleep. The cessation of the noise had satisfied it. For now.

  I slowly climbed out of the cockpit and walked back to the cold, dead forge. Rax, Amelia, and the laborers were staring at the severed winch cable, their faces painted in shades of absolute shock. They hadn't seen the screen, but they saw the physical impossible force that snapped the steel.

  "What... what is down there?" Kael stammered, his scales pale.

  "The apex," I said simply.

  I walked over to the drafting table I had set up on a flat piece of slag. I unrolled the blueprints for the factory floor. I picked up a piece of charcoal and crossed out the entire foundation plan.

  "We don't stop building," I looked at my crew. The terror was still there, but it was hardening into cold, crystalline resolve. "We just change the physics of the assembly line."

  I rapidly sketched new schematics over the old ones. "Kael, start scavenging every piece of rubber, cork, and heavy canvas you can find in the upper levels. Rax, we need to forge heavy-duty suspension springs. Not for the mech. For the anvils."

  I looked down into the dark abyss. "Every piece of heavy machinery gets decoupled from the bedrock. Every drop hammer gets an acoustic dampener. We implement a strict noise quota. We only pour metal when its heart rate is at baseline."

  I slammed my hand down on the modified blueprint. "We are going to build a Stealth Forge. Right on top of the devil's head."