Under the direct mediation of the Ultramarines, the Astra Militarum regiments withdrew to their transports without hesitation, assuming a respectful holding position at the periphery. Following this, a long-range vox-link was established between Axion and Roboute Guilliman.
The specifics of the accord struck between the two remained a mystery to all but themselves.
Shortly thereafter, an Imperial tow-vessel approached the massive field of space debris, dragging the aft section of a Dark Angels cruiser that had been torn asunder. The wreck had already been cleared by search-and-rescue teams; every scrap of gene-seed and every fallen Astartes had been recovered. What remained was little more than a shattered husk containing a damaged reactor core and the primary drive assembly.
It was this massive propulsion system that Axion required.
Before the eyes of the gathered fleet, a miracle of engineering began to unfold. The irregular shards of the space hulk were systematically carved away. Shattered compartments were realigned, and the internal bulkheads of the central hull were purged to create vast, open spaces.
To ensure a continuous power supply for the undertaking, Axion activated the Super Quantum Reactor Core he had previously secured. This core, capable of wireless energy transmission, generated a projection field covering ten square kilometers. In a matter of minutes, the staggering energy output brought every Automated Sentry-Trooper to maximum operational capacity.
The Sentries, wielding humming particle blades, gathered salvaged materials into central caches. These were subsequently processed by the Executor Heavy Tanks, whose nano-swarms deconstructed and reconfigured the scrap into uniform armored plating.
The Eight-Legs units moved with clinical precision, their mechanical manipulators welding these massive, over-sized armor blocks into place. In the zero-gravity vacuum, the efficiency of the automata was magnified exponentially.
Within a mere twenty Terran hours, the once jagged, meteoric wreckage was encased in a fresh skin of metallic armor. The internal silicate rock structures were jettisoned, Aeldari wraithbone was reprocessed, and the remnants of various human vessels were broken down to their constituent molecules and rebuilt.
Axion watched the nano-swarms running at peak load with a touch of regret. Had he possessed more of these microscopic constructors, they could have consumed the entire space hulk and birthed a complete vessel in mere hours. While the swarm lacked the atomic-level perfection of a standard STC assembly line, its molecular precision was more than sufficient for the task at hand.
Given the constraints of raw material, Axion did not demand the impossible.
Once the two disparate hull sections were fused and the breaches sealed, the interior was hollowed out by the Sentries. The resulting internal volume was cavernous, protected by a single, massive hull layer. The "stitching" of the space hulk debris to the cruiser's aft section was completed with startling speed.
When the colossal drive plumes of the cruiser's rear flared to life once more, the onlookers in the Imperial fleet were struck by a collective sense of unease. From the outside, the ship possessed a ramshackle, almost Orkish aesthetic, a crude amalgamation of parts that defied Imperial naval tradition.
Inside, however, the transformation was absolute.
The chaotic mess of the original wreckage had vanished. The hull remained unpressurized, as the Iron Men had no need for oxygen; the ship operated in a cold, silent vacuum. High-density data signals pulsed through the void of the interior.
By Guilliman's decree, the fleet weighed anchor, following the trail of battle deeper into the star system.
For the Tech-priests of the Adeptus Mechanicus, a new ritual was added to their rotation: every few hours, they would observe the "scrap-ship" through their long-range scanners. On the Battle-Barges that had witnessed the initial boarding, all personnel were placed under a strict oath of silence. Aside from the Primarch and the Ultramarines aboard the Dawn of Fire, none knew the truth of what transpired within that hull.
As they traveled, the mysterious vessel continued to evolve. Its silhouette became increasingly streamlined and geometric, the jagged "patches" on the hull smoothing over. What the Eight-Legs had welded, the nanites now perfected, fusing the seams into a singular, seamless whole.
The ship underwent a total metamorphosis. Its silver hull now reflected the light of distant stars with a mirror-like sheen. The aft section, once bearing the heraldry of the Dark Angels, had been stripped of its Gothic ornamentation. The baroque, protruding structures of the cruiser were gone, replaced by an elliptical metallic pillar. The prow terminated in a sharp, conical ram; there was no doubt that if this vessel struck an enemy ship, it would pierce it like a needle through silk.
The exterior was smooth, devoid of any unnecessary protrusions. Even the cruiser's original bridge had been erased. The circular engine exhausts had been reshaped into four-sided squares.
Stunned by this alien design, numerous Tech-Priests and Magi petitioned Guilliman for permission to board and study the vessel. Every request was met with a cold, absolute refusal from the Primarch.
Left with no other option, the Tech-priests could only record their observations in their logs:
Day 1: A crude patchwork reminiscent of xenos "looted" vessels.
Day 2: Hull seams are vanishing. The metal flows like a living thing. The Dark Angels iconography is gone. Protrusions are flattening; the bridge has been absorbed into the hull.
To the Iron Men, this was merely efficiency. A ship required no bridge; sensor arrays were embedded directly into the hull's edge-structure, fused into the skin by the nanite swarms. The quantum core originally designed for Apocalypse-class Titans was repurposed to power the ship's internal systems, though small for a starship, it was more than capable of running the sensors and control logic.
The primary propulsion remained Imperial in origin. Axion repaired the plasma reactors and tuned the engines, feeding the reactor's fires with the slurry of low-grade scrap material. The promethium fuel originally stored in the ship had long since leaked into the void, but the modified engines now burned with a terrifying, simple intensity.
Axion salvaged every weapon system found within the wreckage, refitting them for automated service. The Eight-Legs handled the initial installation, while the nanites fused the mounts into the ship's structure. These hidden batteries were concealed behind retractable armor plating, ready to deploy at a moment's notice. Every macro-cannon was fitted with an automated loading mechanism, completely eliminating the need for the thousands of indentured deck-slaves typically required for Imperial gunnery.
To manage the vessel, Axion constructed a secondary intelligence, a sub-cogitator of such sophistication that it exceeded the logic-patterns of his own guard-automata.
While the fleet cruised, Axion delved into his vast databanks, arming the ship with every weapon system his current energy output could support. Though the Imperial plasma reactors were inefficient by his standards, he simply adjusted the weapon charge cycles to compensate.
Guilliman watched these developments with a heavy heart. He had granted Axion the wreckage as part of their alliance, but seeing a starship transform so radically in the span of hours filled the Primarch with a lingering dread.
Meanwhile, reports from the survivors of the earlier skirmish began to paint a grim picture of the system.
The Daemon-smith Vashtorr the Arkifane had woven a massive conspiracy here, targeting the Dark Angels. The Rock, the mobile fortress-monastery of the Unforgiven, had engaged a colossal daemon-vessel known as an Ark of Omen, a ship the size of a small moon.
Vashtorr had boasted that these abominations were fashioned from space hulks drifted from the Warp. He had also revealed his most blasphemous creation: a twisted world forged from the fragments of Caliban, teeming with the Arkifane's Soul Forges and lakes of black oil. In the height of the battle, the vessel Wrath of Baal had appeared, broadcasting a message that the Primarch Lion El'Jonson was aboard.
The Rock had pursued the enemy, leaving the immediate area. While the survivors confirmed they had received a warning from the Wrath of Baal featuring an image of the Lion, most of the Dark Angels had ignored it, suspecting a chaotic ruse.