The dark purple Psychic Power Scream surged outward from Rena like a world-ending tsunami.
It did not roar like an explosion, yet it carried the deathly, oppressive weight of the depths of the Warp.
Wherever it passed, all tangible matter disintegrated in silence.
The Tyranids' chitinous shells cracked inch by inch, their green bodily fluids instantly boiling into vapour.
The Space Marines' ceramite Power Armour buckled like paper, muffled sounds of shattering bones and dissolving organs coming from within.
Sparks burst from the Servitors' metal bodies, their servo systems utterly destroyed by the Psychic Power impact.
This was a storm of destruction that distinguished neither friend nor foe. Rena's exposed brain-like organ pulsed continuously, pushing the Psychic Power Scream's power to its limit.
Even the organic dome at the top of the nest began to peel away and collapse.
Meanwhile, in District Five of Necromunda's Hive City.
An act of madness worthy of the Underhive's history books was unfolding.
Outside a reserve warehouse in District Five, the Adeptus Arbites guards who normally patrolled without pause had long since vanished.
In their place stood densely packed figures.
They lined the warehouse's metal perimeter walls, stretching from ground level all the way to the ventilation duct junctions.
They had surrounded this temporary Sons of Medusa outpost so tightly that not even water could pass through.
Under the class divisions of an Imperial Hive City, District Five belonged to the middle-level hub, home to lower-ranking nobles, bureaucrats, and technical personnel.
The air here underwent basic filtration, and though the metal walls still bore rust, they showed no obvious corrosion, a stark contrast to the filth and decay below.
Yet the "people" gathered here now were utterly out of place.
From the perspective of the 40K Imperium, they might still have been classified as human.
They possessed roughly humanoid outlines, could use tools, and understood cooperation.
But judged by the standards of Terra in the 3K era, these creatures had long since fallen outside the category of "human."
Extreme scarcity of resources, the Underhive's ceaseless acidic rain and mist, constant exposure to industrial waste, and genetic aberrations caused by prolonged malnutrition.
These had made them malformed products of the Hive City's brutal laws.
Some had arms overgrown with hard keratin shells, like ugly crab claws.
Or both eyes had fused into a single cloudy pupil that could see in the dark.
Others had hunched backs, with clusters of small fleshy growths on the backs of their necks that pulsed faintly with each breath.
They wore tattered sackcloth clothing, their exposed skin covered in scars, ulcers, and mutated tissue.
They gave off a mixture of sour stench, sweat, and rotting flesh, in stark opposition to District Five's "cleanliness."
Inside the warehouse, the Sons of Medusa's temporary outpost was deathly silent.
Three transports stood in the centre of the outpost, their engines long cold, their hulls bearing the Sons of Medusa's insignia.
The outpost's defensive force was so thin as to be almost nonexistent.
Apart from Celeres, a Magos of the Adeptus Mechanicus, there were only two Adeptus Mechanicus apprentices and a few basic Servitors assigned to hauling and sentry duty.
Most of the Skitarii had accompanied Cassius to the Abyssal Spawning Pool.
The forces left behind could handle only routine harassment and had no hope of resisting a large-scale siege.
Celeres stood before the surveillance screen, his red augmetic eye fixed on the surging crowd in the image.
The hem of his robe was embroidered with the Omnissiah's sacred cog emblem, and his left hand had long since been replaced with a precision mechanical hand.
It was now opening and closing unconsciously, its metal joints giving faint clicks.
The thermal imaging on the screen showed that the Underhive crowd far exceeded their estimates, with the preliminary count already reaching four figures.
And scattered figures were still emerging from District Five's alleys, continually joining the encirclement.
"Magos, scans have detected high-energy signatures. At least a hundred targets are carrying Melta Bombs.
"Several hundred others possess improvised explosives."
An apprentice stepped forward. The right half of his face was covered by a mechanical plate, and his voice came through a vocaliser, cold and utterly devoid of emotion.
"How were Underhive slave labourers able to breach the inter-district blockade?
"Neither District Five's checkpoints nor the Adeptus Arbites sentry posts issued any warning signals. This is illogical."
In the Adeptus Mechanicus apprentice's understanding, the Imperium's lowest classes were fundamentally no different from Servitors: both were "inefficient tools" housed in flesh or metal.
The Hive City's class barriers were like a dome of steel. Underhive residents wishing to enter the middle levels had to undergo multiple layers of approval and security screening.
It was no less difficult than having an ordinary person assassinate a Space Marine.
Let alone for such an enormous group to silently bypass every line of defence and surround the Sons of Medusa's outpost so tightly that nothing could get through.
Celeres did not answer immediately. His augmetic eye flickered rapidly as he retrieved surveillance footage from around the outpost.
On the screen, those mutated Underhive residents stood in silence, without shouting or commotion.
There were only pairs of cloudy yet resolute eyes, fixed on the transports.
Most of the Melta Bombs in their hands were shoddy goods from the black market, their casings rust-stained and their fuses exposed. The slightest carelessness could make them detonate in their holders' hands.
The improvised explosives were cobbled together from discarded fuel canisters and chemical agents, the sort of crude devices commonly seen in street brawls.
"Human hearts..."
Celeres suddenly spoke, his voice hoarse, carrying a rare trace of melancholy.
The term sounded particularly strange coming from his mechanically modified throat.
Those long-neglected ancient texts from the 2K era flashed through his memory banks.
Those times without genetic mutation or the corruption of Chaos, when humanity could still freely breathe fresh air.
The ancient texts repeatedly mentioned "human hearts," calling them the strongest and most uncontrollable force.
"Human hearts?" The apprentice froze.
The indicator lights on his mechanical faceplate blinked several times, clearly unable to comprehend this abstract concept.
"What relevance does an organ of the human body have to our current situation?
"We should immediately initiate defensive protocols, activate the transports' engines and break out, or request support from the governor's palace."
Celeres merely shook his head slowly. He knew they had already lost.
The apprentice was about to say more when the surveillance screen suddenly flickered violently.
On the screen, the front ranks of the Underhive crowd moved.
They did not charge, but advanced slowly like a tide, every step heavy and resolute.
Boom!
The first explosion rang out from beneath the warehouse's eastern perimeter wall.
A resident whose arms had mutated into crab claws rushed up beside a transport and detonated the Melta Bomb in his hands without hesitation.
The violent explosion tore his body apart, and scorching metal fragments spattered the transport's hull, leaving deep craters.
Then a second and third explosion followed in quick succession, spreading like falling dominoes.
The Underhive residents pressed forward, one after another. They showed no fear and did not retreat, as though they had long since put life and death out of their minds.
To them, death was not an ending, but the fiercest act of resistance against this brutal world.
The Servitors' Lasguns fired furiously, red beams slashing through the darkness and cutting down those at the front.
But the human tide seemed endless. Whenever one group fell, more immediately filled their places.
The outpost's fortifications continually collapsed amid the explosions. Metal fragments and mangled flesh piled into mountains, and the air filled with smoke and the stench of burning.
In just half an hour, the three transports were reduced to twisted scrap by the continuous explosions.
Their ceramite hull armour had been melted through by Melta Bombs, their engines utterly ruined, leaving only wreckage belching black smoke.
Several hundred Underhive residents still remained in the encirclement, most still holding undetonated explosives.
The survivors neither fled nor continued attacking the outpost. Instead, as one, they tightened their grips on the explosives in their hands.
They exchanged glances, not a trace of hesitation in their cloudy eyes.
Then explosions rang out once more, one after another.
This time, there was no target, no attack, only the resolve to leave no evidence behind.