The internal ecology of Ashfall was nearing a state of perfect equilibrium, but the Seismic Mirror revealed that the external world had not forgotten the mountain. The faint, high-frequency vibrations detected by the Mirror-Readers were the result of an Imperial Heliograph—a system of mirrors used to flash sunlight across vast distances. From the jagged summits of the northern peaks, Arch-Magister Vane's remaining scouts were signaling a distant Imperial survey fleet. They were transmitting the barony's exact coordinates and a detailed report on the subterranean "seismic footprint" they had mapped during the blockade.
The technical challenge was the "Optical Gap." Kael's mountain was a fortress of stone and shadow, but it could not reach the high peaks where the scouts were perched. He needed a way to intercept or distort a signal that traveled at the speed of light. He initiated the development of the Atmospheric Diffuser—a project to weaponize the very smog and steam that the mountain produced.
"If they are using the sun to speak, we will take away their sun," Kael told the Information Citizens. "We cannot climb the peaks to stop them, so we will change the air between us. We will use the Digester's methane and the Bio-Foundry's chemical waste to create an artificial 'Optical Wall'."
The grit of the construction involved the modification of the primary exhaust chimneys. Kael engineered a specialized "Injection Nozzle" at the mouth of the highest vent. By mixing fine particles of zinc-oxide (a byproduct of the foundry) with the high-pressure geothermal steam, he could create a dense, white aerosol cloud that would linger in the cold mountain air. This cloud wasn't just smoke; it was an "Optical Scatterer"—the zinc particles were sized specifically to refract and dissipate the wavelengths of sunlight used by the heliographs.
The physical reality of the "Smoke-Wall" was a grueling coordination of chemistry and weather-tracking. Rylen's surface scouts, moving in the shadows of the limestone ridges, used primitive anemometers to measure the wind speed. They signaled the vault via the acoustic pipes, allowing Kael to time the "puffs" of aerosol to match the wind's direction.
Socially, the High-Peak Signal created a sense of renewed urgency. The population, which had been focusing on internal expansion, was reminded that they were still a target. The newest Aspirants, many of whom had served in Imperial signal corps, were the most effective at "Reading the Blur." They stood in the command vault, watching the Seismic Mirror's light-wall. When the Imperial signal hit the aerosol cloud, the white-washed wall would show a chaotic, shimmering "bloom" instead of a sharp pulse.
A technical failure occurred when the wind suddenly shifted 180 degrees, blowing the zinc-oxide cloud back down into the primary intake vents of the mountain. The "Atmospheric Scrubbers" were immediately overwhelmed by the metallic dust, and the air in the upper residential tiers began to taste of dry copper.
Kael utilized the "Static-Precipitation" bypass. He realized he could use the Galvanic Line to charge the iron grates of the intake vents. By turning the vents into massive electromagnets, he caused the metallic zinc dust to "stick" to the iron bars before it could reach the lungs of the citizens. It was a rapid, electrical solution to a chemical crisis, requiring a massive drain on the battery banks.
The engineering of the Atmospheric Diffuser was a success. The Imperial scouts on the peaks found their mirrors useless; every time they tried to flash a signal toward the horizon, a thick, white mist would erupt from the mountain, turning their precise code into a meaningless glare. The "Optical Wall" had cut Vane's connection to the Empire.
The signal is broken, Elms, Kael said, watching the Seismic Mirror return to its steady, rhythmic hum. Vane is shouting into a blizzard of our making. He cannot guide the survey fleet if he cannot see the horizon.
But as the mountain successfully blinded its enemies, Kael noted that the "Silent Pulse" of the Deep-Rail was becoming slightly more pronounced. The mountain was getting heavier. The construction of Tier 11 and Tier 12 was adding thousands of tons of internal weight, shifting the mountain's center of gravity.
"We are growing too fast for the limestone to hold," Kael noted, his eyes narrowing at the structural tension gauges. "The stone is beginning to 'creep.' If we don't reinforce the primary pillars of the mountain, we won't need Vane to collapse us—the mountain will do it to itself. We need to start the Iron-Skeleton project."
Kael began the designs for Tier 12: The Rib-Vaults—a series of massive, internal iron buttresses that would effectively turn the mountain into an armored, skeletal structure.