Beyond the lethiferous air, the visual occlusion of the emerald haze presented a maddening obstacle. Optical visibility was throttled to less than thirty meters; even the post-human sight of the Adeptus Astartes could pierce the gloom no further than that of a baseline mortal.
The Warp energy saturating the atmosphere played havoc with auspex arrays, rendering ghost signals and static. Communication with the fleet in high anchor was plagued by massive interference. Every soul on the surface felt as though they were playing a blind game of hide-and-seek, groping through the dark for the spoor of Chaos.
Fortunately, the sheer scale of the forces Abaddon had deployed worked against him. The Loyalists soon stumbled upon a gargantuan landing zone. Aside from the scorched earth left by numerous heavy landers and transporters, the ground was churned by a multitude of track-links and heavy tire treads. It was clear that the Archenemy had offloaded significant heavy ordnance alongside their infantry.
Curiously, Imperial archives held no record of this world. Yet, the traitors were moving with the tactical urgency of a force prepared for a full-scale planetary siege.
Finding a fleeting gap in the atmospheric interference, the scouts uploaded their intelligence to the fleet. Aboard the orbiting warships, Data-psalms were performed by the shipboard Data-preachers, evaluating the enemy strength. The consensus was grim: at least hundreds of thousands of Traitor Guard had made planetfall, supported by substantial heavy weaponry.
Furthermore, amidst the chaotic imprints on the toxic soil, scouts identified the distinctive, massive boot-prints of Astartes power armour. Chaos was orchestrating something profound here.
In response, a Dark Angels Strike Cruiser broke formation, descending into low orbit to provide fire support. The moment the scouts pinpointed the main traitor host, the Emperor's Wrath would be delivered via orbital strike.
However, as the reconnaissance teams tracked the foe, the situation grew increasingly aberrant.
The vast Chaos host had blitzed across the surface for dozens of kilometers before disappearing into the maw of a cyclopean complex of ruins. Analysis of the pict-feeds and vox-thief captures suggested the structures likely dated back to the Dark Age of Technology.
Most of the complex had succumbed to structural collapse. Around the perimeter, lingering Warp signatures and fresh detonation craters told a violent story: the traitors had encountered something here, and the meeting had been far from peaceful.
Scattered across the approach were the pulverized remains of cultists and heretics, their flesh still bearing the blasphemous brands of the Dark Gods. But as the scouts pushed just a few hundred meters deeper into the ruins, the carnage escalated into the surreal.
Shattered wreckage was strewn everywhere. The Dark Angels reconnaissance company discovered two Deimos-pattern Predator Executioners bearing the Chaos Star. One was wedged into a collapsed wall, its hull torn open by a massive breach; judging by the twisted adamantium, the assailant possessed claws at least four meters in length.
The other Predator fared worse. Its turret-mounted Plasma Destroyer had been violently twisted into a knot of scrap. The chassis below had been rent asunder, leaving only a mangled skeleton. It appeared that something had physically wrenched the weapon-housing until the volatile energies of the plasma coils suffered a catastrophic containment failure, detonating within the hull.
Beyond these rare relic-tanks, the scouts found even stranger anomalies. Several Land Raiders had been compressed into bizarre, metallic discs. From the narrow seams of these crushed "pancakes," a slurry of gore and unidentifiable matter leaked out. It was evident these transports had been packed with cultists when something, some titanically powerful force, flattened the armored vehicles into iron wafers.
Had the silhouettes of the crushed chassis not been so distinct, the Dark Angels would scarcely have recognized them.
As the search perimeter expanded, the ruins yielded more unsettling sights. An entire squad of World Eaters was found literally "pasted" against a wall, their shattered ceramite and pulped flesh coating the masonry. The scene was a literal slaughterhouse. The Dark Angels could only estimate the casualties by counting the jagged horns of broken helmets.
Symbols of the Black Legion were also found among the debris, but not a single intact corpse remained. In the gutters of the ruined streets, rivers of thick ichor flowed through still-functional drainage systems toward an unknown destination.
Yet, despite the evidence of a massacre, the nature of the attacker remained a mystery. The trail of violence led deeper into the city's heart.
As the scouts reached the urban center, they were confronted by a staggering sight: a gargantuan metallic shaft, over thirty kilometers in diameter, bored straight into the planet's crust. The craftsmanship of this abyss defied identification; its smooth metallic walls appeared almost naturally formed, as if grown rather than manufactured.
Auspex readings of the atmospheric flow suggested that the green miasma choking the planet originated from this subterranean void.
Moreover, the local gravity was fractured. The scouts watched as an artificial river flowing through the city reached the edge of the pit; instead of plunging into a waterfall, the water arced a few meters before sticking to the vertical wall, flowing straight down the side of the shaft. It was as if the gravitational constant inside the hole operated on an entirely different axis than the surface.
Bright crimson tread-marks and bloody footprints on the vertical metal walls, stretching away into the depths, betrayed the traitors' path.
Observing the impossible ninety-degree transition of the tracks, a mortal scout cautiously picked up a piece of rubble and tossed it into the void. The stone fell ten meters, then, with a sharp clack, hit the vertical wall as if it were solid ground.
"My Lord, the gravity here... it is twisted. Do we descend?" the scout asked, his voice wavering with uncertainty before the Angels of Death.
The Dark Angels, however, noted details the mortals missed. From the design of the metal walls and the precision of the water's flow, they were certain this was no manifestation of Warp-sorcery. The most logical conclusion was that a portion of this ancient ruin was still operational.
"Continue the advance. Leave half the strength here to establish a perimeter," ordered the Dark Angel.
The mortal scout struck his breastplate in an Aquila salute and turned to relay orders. Unlike the Astartes, who carried little beyond their holy armaments, the air-dropped Chimeras were laden with field gear.
Signal flares were ignited, their ancient chemical burn piercing the haze to regroup the scattered reconnaissance teams. Over a dozen Chimeras rumbled to the site, crashing through debris to form a defensive ring. Utilizing the high-output vox-arrays mounted on the transports, the scouts finally pierced the Warp-interference, restoring a tenuous link with the Strike Cruiser in orbit to report their discovery.