Given that a large host of Watchers in the Dark had vanished alongside the Lion, the Dark Angels easily deduced that their Primarch had likely made planetfall on Wyrmwood. However, violent surges of empyrean energy severed all communication between the surface and the fleet. Under normal circumstances, they could have easily triangulated El'Jonson's position at this range; now, even the massive localized auspex arrays of the capital ships failed to yield anything beyond static.
The fleet conducted an orbital reconnaissance sweep, but to their frustration, every scanning method was crippled by severe interference, leaving only the sight of swarming daemons visible to the naked eye. Faced with this inability to achieve a lock, Roboute Guilliman turned to Axion for assistance.
The sensor suites of the Pectaro were similarly hampered. Even with Axion personally overseeing the task, loading multiple heuristic algorithms to filter the Warp-noise, the results were negligible. The signal from a single suit of power armor was simply too faint amidst the psychic storm.
With electronic measures blinded, optical reconnaissance became the only recourse.
High-resolution orbital captures were taken of the entire planetary surface. Powered by the immense processing capacity of a machine intelligence, these images were magnified, stitched, and tiled into a comprehensive map. Such a feat of rapid, exhaustive data synthesis could only be achieved by an Iron Kin.
As the analysis concluded, Axion detected an anomaly almost immediately.
On a plain choked by lakes of black promethium and oil, dozens of destroyed daemon engines lay scattered. Their wreckage formed a distinct trail of destruction, a directional arrow pointing straight toward a nearby chasm. Axion trained the ultra-high magnification optical arrays on the area. Soon, the silhouette of a golden-haired figure clad in black plate, wielding a shield and a radiant blade, came into focus.
Through simple visual pattern matching, Axion had found the Lion.
This development utterly derailed the machinations of Vashtorr the Arkifane. Originally, the daemon-smith had intended to lure the Dark Angels into a grueling, blind search for the relic across the surface of Wyrmwood. He aimed to bleed the Unforgiven dry in a war of attrition, sating his thirst for vengeance. Once Guilliman inevitably departed, Vashtorr believed he would have another opening to finalize his grand designs.
But fate, and the ancient machine, had other plans.
The Lion had been pulled directly onto the world by the "Forest-walk," appearing mere leagues from the Forge-Palace where the Ouroboros was interred. Now, the ensuing orbital bombardment and drop-pod assault descended with the terrifying precision of a surgical strike.
The daemon cohorts Vashtorr had scattered across the world to draw the Imperial forces into a chase were now tactical liabilities. As the skies turned black with macro-cannon shells, they were followed by a torrential rain of Drop Pods and heavy Thunderhawk gunships.
The daemons below were banished back to the Warp in instant, explosive bursts. Daemon engines, once terrifying, were reduced to scrap metal by the direct impact of macro-ordnance.
The Lion, watching the sky fill with the fires of re-entry, noted the timely arrival of the support. He wondered briefly how the fleet had managed to pinpoint his location. He had attempted to broadcast via his armor's vox-systems, but the only response had been a wall of cacophonous interference.
The earth shuddered as Drop Pod after Drop Pod slammed into the soil. Massive armored hatches blew outward, and ranks of Dark Angels stepped onto the surface of what was once their home.
The moment their boots touched the ground, every son of Caliban felt it: the psychic lamentation of the planet's soul. They felt a strange, magnetic pull, a summons resonating within the Lion's own genetic code.
Recovering from the shock of the bombardment, the daemonic hosts began to converge from across the planet. In the low orbit above, the warships continued to provide fire support, their lances lashing out to incinerate daemon engines the size of Titans, easing the pressure on the ground forces. Dark Angel Ravenwing bikers tore across the landscape, kicking up plumes of ash as they scouted the perimeter, while mortal auxilia began fortifying landing zones to secure the beachhead.
Guided by the Watchers in the Dark, the Lion led his vanguard toward the source of the world-soul's agonizing cry.
The atmosphere was thick with industrial toxins and the stench of rot. A contingent of mortal soldiers advancing alongside the Astartes collapsed after barely a few hundred meters; the air was saturated with a Warp-plague that defied standard filtration. As the thick gray ash began to take on a sickly, iridescent green hue, even the Lion's expression darkened with caution.
Towers of bloated shadow loomed through the haze, accompanied by the wet, squelching sound of bursting bubbles in a mire. A mountain of tumescent flesh, radiating decay and poison, lurched out of the fog.
"A daemon of Nurgle?!"
Blocking their path was a Great Unclean One. Corruption sloughed off its body in necrotic sheets. Under its influence, the barren ground suddenly erupted with perverted life. Alien flora burst from the soil—thorny, twisting vines that grew and rotted at an impossible, sickening rate. These decaying plants moved with a predatory sentience, writhing and snapping. For a fleeting second, the warriors felt as though they had been plunged into the lethal jungles of Catachan.
Swarms of Nurglings spilled from behind the Great Unclean One like a living tide, shrieking as they threw themselves at the vanguard. The Greater Daemon let out a wet, wheezing laugh, swinging a massive rusted flail as it charged.
The plague spread with unnatural speed. Even the fresh daemon engines passing near the Great Unclean One were instantly mapped with rust and pitted with sores. Their profane cannons began to spit shells coated in lethal viral spores.
BOOM!
A pillar of incandescent, crimson flame erupted from the rear of the Imperial column. The heat was so intense it seared the very air, leaving a scent of ozone and charred waste. A blue-armored figure, shoulder-deep in a mantle of fire and wielding a burning sword, strode forward.
While Roboute Guilliman fundamentally disapproved of the Lion's penchant for secrets and "unnecessary" diversions, he had decided that his intervention might prevent his brother from wasting further time on this blighted world.
The holy fire scoured the plague from the air, tracing a path of purification directly to the source of the contagion: the Great Unclean One itself.
The Dark Angels watched in awe as the Primarch's fire swept past them, leaving them untouched while the Greater Daemon's massive form was wreathed in agonized shrieks. The power of the Emperor's sword was undeniable.
"Agh! How?! I—!!!"
Through the blinding glare of the flames, the Great Unclean One caught sight of the blue-clad giant. It recognized the armor and the sun-bright blade immediately.
"Roboute Guilliman?!" the daemon howled. Having encountered the Avenging Son before and knowing the finality of his blade, the Great Unclean One did not hesitate. It dragged its burning, mountain-sized carcass backward, tearing a jagged rift in reality and fleeing back to the Warp.
A stunned silence fell over the battlefield, shared by the Dark Angels and both Primarchs alike. It was broken only by the daemon's fading, furious roar echoing through the rift:
"VASHTORR! YOU DARED TO DECEIVE ME!"