As Vonlense ascended to one of the fortress's firing towers, the full breadth of the slaughter was laid bare before him. A strange light flickered within his clouded, aged eyes.
"Guard, notify the civilians gathered within the keep. Rally every soul capable of holding a blade or a rifle, man or woman alike! And tell the Ministorum priests to lead us in one final prayer, here, upon the field of battle!"
With those commands issued, Vonlense took a vox-caster from a nearby sentry. His voice, ancient yet resonant with unyielding authority, echoed throughout the stronghold of Tourena.
"This is Marshal Vonlense of the Planetary Defence Forces. Reinforcements are imminent. Hope lies just ahead. To every soul: take up your arms and fight to the final breath. For the Emperor!"
BOOM!
A dull, heavy thud reverberated from the fortress's foundations. The void shields enveloping the outer works flickered once and collapsed into nothingness. The combined bombardment of the Hierophant's twin bio-cannons, coupled with the relentless fire of Hive Guard and bio-beasts, had finally overstressed the shield generators.
A beam of toxic green energy, no longer hindered by the shimmering barrier, slammed directly into the fortress's outer curtain wall. A titanic explosion billowed toward the sky. Nearby Earthshaker cannons were instantaneously consumed by the blossoming firestorm. In the heavens, the swirling swarms of Gargoyles began a frenzied, screeching dive.
THUD! THUD! THUD!
Suddenly, a wall of dense projectile fire erupted from the fortress's flank, obliterating the diving Gargoyles and the Harpy leads in a storm of lead. Shattered xenos carcasses rained upon the earth, crushing several unlucky PDF soldiers beneath their weight.
Vonlense narrowed his eyes. The fortress's small-caliber anti-air arrays had long been silenced; this volume of fire was certainly not from the las-weaponry of the PDF.
BANG! BANG!
The rhythmic, heavy thunder of bolter fire suddenly erupted across the trenches. A host of Astartes clad in black power armor, wreathed in flickering, ethereal flames, materialized abruptly upon the battlefield.
Vonlense grabbed his magnoculars, frantically scanning the front lines. Their shoulder pauldrons bore no Chapter markings. Aside from grim skull iconography, there was no identifying heraldry upon these black-clad scions.
"Guard! Determine the origin of these Angels of Death immediately!"
Without waiting for a response, Vonlense watched the harbingers of doom through his lenses, then roared into the vox-caster.
"The Emperor has sent His Angels to deliver us! Fight with the fury of the righteous! For the Emperor!"
Vonlense made a rapid tactical assessment; there were hundreds of these black-armored Astartes. He then swung his magnoculars around, searching the surrounding landscape. Though the sudden arrival of aid filled him with fervor, as a Marshal of the PDF, he could not succumb to blind optimism. If these few hundred Astartes were the sum of the relief force, it would not tip the scales. The planet was already lost, with hundreds of millions of xenos infesting the surface.
Yet, no matter how hard Vonlense searched the skies or the horizon, he found no further trace of an incoming force. There were no Thunderhawks soaring through the clouds, no contrails of drop pods. There was nothing. It was as if these silent warriors were the entirety of the Emperor's mercy.
As Vonlense struggled to solve the riddle of their origin, the guard returned.
"Report! My Lord, the soldiers on the front lines have no knowledge of where these Angels came from. They simply appeared within several lost trench sectors. Even now as they fight alongside our men, they issue no commands and offer no words; they fight with a silent, preternatural coordination. None know their port of origin."
In that moment, Vonlense fell into a stunned silence. Would the Emperor truly cast His Angels into a war where no hope of victory remains?
Refusing to surrender to despair, Vonlense scanned the distance once more. What he saw only served to deepen his dread. Further off, more Tyranid bio-titans were lumbering toward the fortress. The heavy ordnance on the Imperial side was being rapidly depleted. Sparse counter-battery fire did little to slow the advance of the colossal xenos; even when a shell found its mark, it caused only superficial trauma.
Every time the Hierophant's bio-cannons spoke, an entire platoon was vaporized. Leman Russ and Macharius tanks suffered the same ignominious fate; a single direct hit reduced the pride of the Imperial motor pools to molten scrap.
As the battle ground on, Vonlense felt his despair returning, the hope sparked by the Astartes' arrival beginning to gutter like a dying candle.
Suddenly, a blinding flash of azure light erupted above the battlefield. A massive sphere of blue energy descended from the firmament, striking the heart of the swarm with pinpoint accuracy and incinerating everything within a radius of several kilometers.
The collective psychic shriek of the dying swarm pierced the ears of every mortal present. Only the black-armored Astartes remained unfazed, their fingers never leaving their triggers, their blades never ceasing their rhythmic slaughter.
Then, a gargantuan roar descended from the heavens. A shadow loomed over the earth, and a violent downdraft extinguished the remnants of the blue firestorm. A colossal, silver-sheathed crate-like structure, having undergone a massive deceleration burn, slammed into the ground. The impact tremor was so violent it was felt even within the fortress's deepest bunkers.
Vonlense had no doubt that had the object not decelerated, it would have crushed several bio-titans by kinetic force alone. What followed left him staring through his magnoculars in a state of catatonic shock.
The sides of the structure deployed outward, the heavy base and unfolding walls acting like a monolithic flyswatter, flattening the encroaching Tyranids into the red earth. From the center of this massive cargo array, strange automata began to pour forth, unleashing a frantic hail of fire upon the xenos.
Rows of rapid-fire turrets rose from the base structure, laying down a carpet of suppressive fire against the Tyranids. Soon, a central container slid open. Ranks of silver-white automata leaped from the hold. Under the cover of the automated turrets, they formed firing lines and began to systematically purge the swarm.
A Tyrant Guard, relying on its thick carapace to shrug off solid-slug fire, charged the new arrivals. However, four or five beams of intense orange light easily pierced the heavy shell that was usually immune to standard lasgun fire, detonating the beast into a ball of ichor and flame. Still, the silver machines continued to pour from the containers in an unending stream.
The Hierophant outside the fortress began to slowly turn its massive bulk; evidently, the threat to its rear was far greater than the garrison before it. But as it completed its lumbering turn, two gargantuan shells struck the center of the bio-titan's torso. The impact tore a massive crater in its flank and severed one of its primary legs.
The shriek that erupted from the Titan's maw shattered the air of the battlefield. Vonlense could have sworn that the tank visible in his magnoculars was the largest ground vehicle he had ever seen in his life, larger even than a Warhound-class Titan.
Two more high-explosive shells screamed through the air from the massive twin barrels. They struck the Hierophant's low-slung head with absolute precision, and the ensuing explosion swallowed the titan whole. The bio-cannon it had been charging detonated prematurely, the back-blast obliterating a swarm of nearby xenos. Green ichor and chitinous shrapnel rained across the field.
The surrounding Tyranids seemed to freeze as if gripped by a sudden, collective shock, before beginning a frantic retreat. This was the first time in over a month that Vonlense had seen the swarm give ground.
Just as he shifted his focus to the retreating swarm, a shadow even larger than the bio-titans fell across his vision.
"By the mandate of Roboute Guilliman, Lord Regent of the Imperium, reinforcements have arrived! The Legion is deploying. Stand clear."
A booming, synthesized voice thundered from the gargantuan shadow in the distance, reaching the ears of every soul outside the fortress. And as the survivors stood transfixed by this sudden turn of fate, none noticed that the black-armored Astartes had once again vanished from the front lines into thin air.