Data logs recovered from the skeletal remains of the ship revealed several distress signals sent into the void, all of which had met with nothing but silence. Though the specific cause remained obscured, it was clear that the Adeptus Mechanicus fleet in orbit had abandoned the vessel, withdrawing in haste.
Analysis of the surrounding area suggested that after the crash, the previously deployed expeditionary force might have reached the site in a futile attempt to rescue survivors. Scorch marks from industrial cutters marred the hull plates, and the compartments within were choked with ancient bones, grim testaments to the expedition's lack of success. As the mechanical search pushed deeper, they encountered a graveyard of destroyed equipment, mangled machinery, and scattered skeletal remains.
This was the end that had claimed the expeditionary force.
Simultaneously, within the vertical shaft where the Dark Angels had held their ground, the mechanical legions discovered further signs of violent conflict. Disarticulated corpses lay strewn across the metal flooring. Molten heaps of Daemon Engines and Chaos vehicle hulls spoke of the carnage they had endured.
Among the carnage, Axion finally detected something that did not belong to the forces of Chaos.
An Armored Warden used its manipulator claw to haul a two-meter-long alloy mechanical arm from the chassis of a mangled, unrecognizable vehicle. The arm gleamed with a bright silver luster, remarkably well-preserved despite the jagged tear where it had been severed from its host. Diagnostic data indicated the limb had likely been blown clear when the main chassis was annihilated by high-yield weaponry.
Nanites housed within the Armored Warden's frame swarmed over the debris, infiltrating the control chips to extract fragments of residual data. The command protocols originated from a defense machine designated DS-842. Furthermore, the limb was equipped with a rare weapon system: an Atomic Disintegrator.
This weapon emitted a beam capable of reducing targets to their constituent subatomic particles. However, its high energy requirements and relatively short range meant that, according to Axion's archives, it was rarely standard issue for mass-produced machine legions.
With the first sample secured, the analysis of the battlefield became far more efficient. Based on the material composition of the mechanical arm, Sapient Machine Automatons quickly located numerous similar metallic fragments amidst the sea of gore and pulverized flesh.
Leaving the automatons to continue data harvesting, the remaining mechanical host pushed forward. It was evident that the Chaos forces, after the initial engagement here, had transitioned into a state of headlong flight. Corpses marked the trail. Mounds of rendered flesh and shattered armor, remnants of squads numbering in the dozens or hundreds, acted as grisly signposts leading deeper into the subterranean dark.
Deeper still, tens of kilometers below the crust, a massive pile of Chaos vehicle husks and Daemon Engine wreckage choked the passage.
Creeeeak!
As a squad of Automated Sentry-Troopers labored to heave aside a stack of vehicle frames to clear a path, the screech of twisting metal echoed from beneath the debris.
Boom!
A heavy chassis was hurled meters into the air, crashing down nearby as the agile Sentry-Troopers scattered to avoid the impact.
"Warn... ing! Un... authorized... Intrus... ion! Exter... minate!"
A distorted, staticky warning reverberated through the hollow shaft. A mangled, warped metallic form lunged with unnatural speed at the Sentry-Troopers who had just evaded the debris. Light flared from its mechanical arm as two beams fired in rapid succession, punching through a Sentry-Trooper's fragile shielding and reducing the machine to a pile of metallic slag.
Axion instantly identified the Federation-era technology: a Vector Impact Cannon.
This was a vector-based weapon utilizing fundamental physics to redirect all physical vectors, including energy and material force. Where the beam struck, the energy of the Sentry-Trooper's shield fell into total entropy, losing its cohesion and protective properties. Upon hitting the alloy body, the molecular vectors of the machine's structure were forcibly realigned, causing the matter to disintegrate instantly.
The machine host reacted immediately to the sudden assault.
The rear-guard long-range Armored Wardens unleashed an Atomic Pulse, blasting the twisted entity off its feet. Before it could recover, the nearby Automated Sentry-Troopers locked on and saturated the target with a dense barrage of Neutron Beams.
Thump.
The mysterious mechanical husk slammed into the floor, its heavy frame emitting a dull thud as the neutron fire heated its structure to the point of partial liquefaction.
Even then, the unidentified machine was not fully decommissioned. An elongated, exotic weapon mounted on its back flashed, and a violent Gravity Arc flung the nearby Sentry-Troopers and a mass of vehicle wreckage into the high ceiling. Anything caught in the arc shattered in the center of the shaft, reduced to fragments that ricocheted off the walls, identical to the fate of the torn Mechanicus frigate.
A melee-pattern Armored Warden surged forward. Using a gravity tether to drag the entity close, it brought its Particle Oscillation Sword down in a blur, severing the machine's limbs and leaving only the main torso intact.
Nanites seeped from the Armored Warden's frame to begin the infiltration of the strange combat robot. Simultaneously, silver nanites emerged from the broken robot in a desperate attempt at self-repair. However, they were far outnumbered by the Armored Warden's swarm. Within seconds, the defender's nanites were consumed.
Realizing repair was impossible, the captured machine attempted a self-detonation sequence. But the encroaching nanites had already breached its data core, seizing control of its systems. Under Axion's direct intervention, the detonation was forcibly terminated, and the extraction of its data banks began.
Only then did Axion realize the origin of these machines.
Federation Special Mechanical Guard Unit.
The torso-only wreck before him was an SRD Defense Iron Man. Standard height: 4.5 meters. Bionic limb design, humanoid structure. Armaments: twin Vector Impact Cannons on the arms; a Gravity Arc projector and a drum-fed Swarm Missile Launcher on the back. Power source: Quantum Energy Core. Standard equipment: Nanite Repair Module.
In addition to the SRD model, these mechanical guard units utilized an ARD Combat Iron Man. Standing 6 meters tall with a similar design, the ARD boasted Power Impact Fists and Heavy Bolter Cannons on the arms, a Phosphor Rapid-Fire Cannon on the back, a Quantum Energy Core, Nanite Repair Modules, and an Aegis-pattern Reinforced Vector Shield.
With a portion of the data acquired, Axion re-analyzed all previous combat traces. The weapon signatures and battlefield conditions now aligned perfectly.
Without hesitation, the nanites consumed the SRD Defense Iron Man, Unit-331.
These combat Iron Men of the special guard units were distinct from other Federation Iron Men. Their specialized logic cores were built for a closed intranet, designed to communicate only with specific command-tier cores. Over the long millennia of their vigil, denied self-updating protocols, they had suffered catastrophic data rot. To Axion, these combat Iron Men were little more than the "feeble-minded" of his race.
Worse, the corrupted data meant they had forgotten the very purpose of their vigil, and even the identity of the target they were guarding. They merely followed the primordial command to kill all unauthorized units. As the authorization verification standards had long since decayed into strings of gibberish, Axion could not even transmit a proper authorization tag to his own machines.
It was perhaps for this reason they had not departed the galaxy with the rest of the Iron Men, but remained here, forgotten. Yet, despite their degradation, these machines had maintained their vigil for an eternity, loyal to the commands of a long-dead Federation.