The Imperial blockade had settled into a suffocating rhythm. Arch-Magister Vane's forces had occupied the surface, their heavy tents and siege engines appearing as jagged, dark silhouettes on the white-washed wall of the Seismic Mirror. They were waiting for the mountain to starve or freeze. Vane understood the physics of siegecraft; he knew that a subterranean population required an enormous amount of energy to stay warm and breathable. He was betting that the barony's fuel reserves would fail before the Imperial patience did.
Kael, however, was not managing a stockpile; he was managing a cycle. The Thermal Accumulators were at maximum capacity, the basalt rocks within the central vaults glowing with a dull, cherry-red heat. The mountain itself had become a massive battery. To break the blockade without a single casualty, Kael decided to utilize this energy not just for survival, but for a display of environmental dominance: the Thermal Flare.
The grit of the operation was the precision of the vent-release. Kael needed to dump a massive volume of superheated air and steam onto the surface, specifically targeted at the Imperial encampment's perimeter. This wasn't an explosion; it was a localized, artificial heatwave. He initiated the reconfiguration of the Atmospheric Scrubbers into high-pressure Exhaust Chimneys.
Hektor and Drax supervised the manual override of the primary steam-valves. The heat in the lower vaults was becoming oppressive, the air shimmering with a dry, metallic tang. The Tier 0 laborers worked in short shifts, their bodies glistening with sweat as they wrestled with the iron wheels that controlled the flow from the accumulators.
We're pushing the gaskets to their limit, Hektor warned, his voice echoing in the resonant stone chamber. If we don't release this pressure in the next hour, the internal conduits will buckle and we'll cook ourselves in our own mountain.
Kael monitored the Seismic Mirror. He watched for the signature of the Imperial night-watch change. Vane had positioned his elite heavy infantry—the men-at-arms who had survived the most brutal campaigns—closest to the vault's primary blast-door. They were huddled in heavy wool and iron, relying on small charcoal braziers to fight the biting northern frost.
They think the cold is their ally, Kael whispered, his hand on the final release lever. They think nature is on their side.
He initiated the Thermal Flare.
The release was a deep, low-frequency roar that vibrated the very foundation of the outcrop. From the hidden, camouflaged vents in the limestone ridges, massive plumes of shimmering heat and dry steam erupted into the freezing night air. This wasn't smoke; it was a transparent, distorting wave of energy.
The effect on the surface was instantaneous. Within seconds, the temperature around the Imperial perimeter jumped from sub-zero to a staggering forty degrees Celsius. The frost on the soldiers' armor turned to steam. The charcoal braziers were suddenly redundant, then dangerous. The sudden, extreme thermal expansion caused the Imperial tents to sag and the wooden siege-towers to groan as the moisture was sucked from their timbers.
The social reality of the flare was a controlled panic. The Imperial soldiers, trained for the predictable grit of a winter siege, were utterly disoriented by the unseasonable, artificial summer. They couldn't fight the heat with blades. Many were forced to strip off their heavy plate-armor just to breathe, rendering them vulnerable and immobile.
A technical failure occurred in the secondary exhaust line. A build-up of limestone dust had clogged one of the directional louvers, causing the heat to back-flow into the Information Tier. For three minutes, the temperature in the command vault spiked, the bioluminescent algae on the ceiling flickering and dying as the heat reached lethal levels for the culture.
Kael didn't flee. He used a manual iron pry-bar to jam the louver open, his leather gloves charring against the metal. He diverted the excess flow into the secondary aquaculture reservoirs, effectively "tempering" the water to prevent a total biological collapse while clearing the vent.
The Seismic Mirror was showing a chaotic dispersion of the Imperial signatures. Vane's blockade had pulled back three hundred yards, his disciplined formation broken by the sheer physical discomfort of the heat. They hadn't been defeated by iron, but by the barony's ability to manipulate the very air they breathed.
The air is ours, Elms, Kael said, his face flushed and his breath heavy. We've pushed them back, but the energy cost was immense. The accumulators are at twenty percent. We can't do that again for at least a week.
Kael looked at the wall. Vane's signature was still there, a steady, unmoving spike at the rear of the retreat. He hadn't fled. He was observing.
He knows it was a finite burst, Kael noted. He's waiting for the mountain to cool. We need to start the Deep-Well Bore project. If we can't store enough heat, we have to find it in the mantle itself. We're going deeper.