The final Axle Train had barely reached the regional capital before the response arrived. It was not a herald of gratitude, but a specialized logistics company of the Imperial Guard, escorting a carriage of polished black lacquer. From it stepped Arch-Magister Vane, the Crown's Chief of Materiel. Vane did not look at the axles; he looked at the smoke rising from the northern horizon. The "Stone Plug" had secured the bridge, but it had also signaled a level of engineering sophistication that the Empire could no longer allow to remain "autonomous."
"The axles are adequate, Baron," Vane said, his voice like the grinding of dry parchment. "But our surveyors have reported a 'heartbeat' in the earth at Outpost Alpha. A rhythmic force that pumps ten thousand gallons of water an hour without a single ox. The Emperor does not require more wheels; he requires the Prime Mover."
Vane presented a formal Imperial Writ: The Sovereignty of Ashfall is recognized, contingent upon the delivery of one functional atmospheric engine and the associated technical schematics to the Capital Forge.
Kael felt the "grit" of this new entrapment. To hand over the steam piston was to hand over the key to the future. Once the Empire had the engine, Ashfall would become a mere footnote, a resource to be drained until the machines in the capital could be replicated. He had to provide a prototype that satisfied the writ but protected the "Source Code" of his technology.
"The engine is a temperamental beast, Arch-Magister," Kael replied, leading Vane toward a secondary "Demonstration Shed" he had prepared. "It requires specific thermal conditions and a labor force trained in its... eccentricities. To move it is to risk its soul."
Kael initiated the Black-Box Protocol. He had Hektor and the Tier 0 crew construct a "Diplomatic Prototype." On the outside, it was a massive, impressive assembly of iron and brass, covered in unnecessary cooling fins and complex-looking manual levers. But the internal mechanism was a "Simplified Cycle."
The technical deception was subtle. Kael utilized a Variable-Timing Cam that was purposefully inefficient. While the engine would function and pump water, it consumed four times the fuel of the actual Ashfall pistons and suffered from "Thermal Fatigue" after only six hours of operation. To a capital engineer, it would look like a miracle of power; to Kael, it was a mechanical dead-end.
"We must insulate the schematics," Kael whispered to Elms in the drafting room. "We will provide them with the 'Gross Geometry'—the sizes of the cylinders and the stroke of the beam. But we will omit the Expansion Ratios and the specific alloy composition of the piston seals. Without the chemistry of the tallow-lead mix, their pistons will seize within a week."
Socially, the "Prototype Demand" created a wave of internal paranoia. The "Information Citizens" realized that their knowledge was now a state secret. Kael implemented the Fragmented Knowledge Policy: Hektor's smiths knew the metallurgy; the Telegraphers knew the timing sequences; the Miners knew the fuel ratios. No single person, other than Kael, held the complete mathematical model for the steam piston.
Vane was not easily fooled. He spent three days in the Demonstration Shed, measuring the stroke and the coal consumption with a silver stopwatch. He noticed the thermal fatigue.
"It runs hot, Baron," Vane observed, touching the glowing iron of the cylinder. "The efficiency seems to drop as the day wanes. Is this a limitation of the design or the fuel?"
"It is a limitation of the frontier, Arch-Magister," Kael lied smoothly. "The iron here is 'Young Iron.' It lacks the thermal stability of the coastal ores. Perhaps in your capital forges, with your superior materials, the engine will find its true potential."
The "Diplomatic Prototype" was being loaded onto a heavy, twelve-ox sled for the journey south. Kael watched it go, a Trojan horse of inefficient iron. He had given the Empire what they asked for, but he had effectively "poisoned the well" of their innovation.
"They have the iron, Elms," Kael said, his eyes reflecting the fading light of the Gray Fang. "But they don't have the math. When that piston seizes in the capital, Vane will come back. And next time, he won't bring a carriage. He'll bring a legion to 'escort' me to the capital for questioning."
Kael turned toward the northern mines. "We need to finish the Defensive Perimeter. If the Empire wants the heart of Ashfall, we'll make sure it's buried under ten thousand tons of limestone before they can touch it."