As they neared the seething mass of mutants, the once-confident Imperial infantrymen grew tense.
Their lasguns primed. Their armor was sealed. Their formation held. None of that kept fear from tightening around their throats.
Ahead of them, the corridor writhed. Chitin scraped against ferrocrete. Mutated limbs dragged through old blood and powdered dust. Too many bodies pressed together in the narrow passage, hunched and twitching beneath the cold light of distant orbital fire bleeding through cracks in the hive's wounded shell.
Before the counteroffensive, these things had owned the dark. They had stalked derelict hab-stacks, service tunnels, collapsed manufactoria, and forgotten underhive corridors, tearing apart entire squads with claws strong enough to split flak armor and jaws that did not care whether a man died screaming or praying.
Every soldier present had seen the aftermath. Some had watched comrades vanish under a tide of limbs. Others had only heard the echoes through vox-static: the wet crunch of bodies, the burst of lasfire cut short, the last frantic calls for support that never arrived in time.
To the men and women advancing behind Grot, the mutants were monsters.
Xenos-corrupted abominations. Living proof that the human form could be stolen, twisted, and worn like a joke by something beneath contempt.
But to Grot?
They were only slightly thicker than the usual enemy after being crushed beneath his gravitic hammer.
"BOOM—!"
Grot's roar rolled down the corridor with the force of a mortar blast as his hammer struck the floor. The weapon's gravitic core flared for a fraction of a second, and the impact sent a concussive pulse through the dust-choked passage. Loose cables snapped overhead. Rust flakes rained from ancient pipes. The walls groaned as if the hive itself had been punched awake.
The mutants turned toward him.
At first, they moved sluggishly, hollow-eyed and almost confused, their warped faces twitching as though listening to a voice too distant for human ears. Then something inside them remembered hate. Their bodies convulsed. Spines bent. Claws flexed. A low, wet chorus of snarls spread through the mass before erupting into a shrieking charge.
"Come on, you xenos bastards."
Grot tightened both hands around the haft of his gravitic hammer. His jump pack growled to life behind him, heat washing over the soldiers at his rear.
Then he charged.
The first two mutants barely had time to react before his armored bulk hit them. One vanished beneath his shoulder plate with a crack of collapsing bone. The other flew backward, slammed into the ferrocrete wall, and left a dark, broken smear where it struck.
Grot swung before their bodies finished falling.
The hammer moved in a brutal arc, heavier than any human weapon had a right to be and guided with the easy familiarity of a man who had already solved the problem of fear by deciding it belonged to the enemy.
The gravitic field around the head pulsed on impact, compressing flesh, chitin, and bone in a localized crushing wave. Mutants caught near the strike were yanked off balance, folded inward, and hurled against the walls like insects caught in an industrial press.
The corridor became violence.
Grot moved like a living avalanche, but not a clumsy one. He was huge, loud, and direct, yet there was purpose in every step. When claws swept toward his throat, he ducked beneath them with surprising agility for a man in power armor.
When a mutant lunged low, he drove a knee into its chest and smashed it aside before bringing the hammer down on its skull. When another tried to circle around him, a short burst from his jump pack carried him sideways, his shoulder slamming into the creature hard enough to send it tumbling into three more behind it.
The infantry behind him watched in grim fascination.
They had been taught to fear the mutant charge. They had been taught to hold formation, maintain fire discipline, and sell every meter of corridor with blood if necessary. Grot did not sell meters. He took them.
A mutant vaulted over the bodies clogging the floor and came for his flank, all hooked talons and distended jaws.
Grot dropped low, drove one gauntleted hand into its abdomen, and fired the scatter-laser built into his forearm. The close-range discharge punched through the creature's torso in a burst of hard white light. Its insides cooked, ruptured, and sprayed out behind it in a steaming fan.
"Too close," Grot muttered, shoving the corpse away. "Bad manners."
Another mutant died under the hammer.
Another fell with its ribcage compressed into pulp.
Another lost its head when Grot caught it on the backswing and painted the ceiling with gore.
The slaughter continued.
Grot activated his gravitic shield only when necessary, saving power with the practical instincts drilled into every Thunderborn by Qin Mo's relentless complaints about waste heat, energy inefficiency, and soldiers who mistook invulnerability for permission to be stupid.
Solid rounds, claws, and chunks of broken metal flattened against the distortion field when he raised it. The rest of the time, he trusted armor, momentum, and the hammer.
The mutants kept coming until their numbers finally began to thin.
By then, the corridor was slick underfoot. The air was hot with blood-mist, ozone, burned meat, and the metallic stink of opened bodies. The walls were no longer gray. They had been coated in layers of red, black, and glistening alien ichor.
Grot's breathing grew heavier inside his helmet. Not from fear. Not even true exhaustion. The armor could carry most of the load, but violence still had rhythm, and rhythm still demanded effort.
When the last dense knot of mutants surged toward him, he holstered the hammer across his back and raised both shoulder-mounted cannons.
"Enough of this."
The cannons woke with a rising whine.
Searing volleys tore through the corridor, overlapping beams and explosive pulses chewing through the remaining horde. Mutants vanished in flashes of heat and pressure. Limbs came apart. Torsos burst open. Those not killed outright were flung backward into the press behind them, turning the final charge into a collapsing heap of burning bodies.
The corridor trembled beneath the weight of his firepower.
Then, at last, there was silence.
Not clean silence. The dead still settled. Fluids still dripped. Somewhere a wounded mutant twitched until one of the infantrymen put a lasbolt through its skull. But the charge was over. The passage belonged to the Imperials again.
Grot lowered his cannons and surveyed the mountain of corpses around him.
"That's it."
A few soldiers stared at him as if trying to decide whether to cheer, pray, or simply keep breathing. One made the sign of the Aquila with shaking fingers. Another laughed once, too sharply, then swallowed the sound before it became hysteria.
An officer stepped forward, boots slipping slightly in the gore. He forced himself not to look too long at the crushed remains underfoot and pointed toward a sealed chamber at the end of the passage.
"Sir. You might want to check what's inside that room."
Grot turned his helmet toward the door.
He blinked.
"Ah. Right. Almost forgot."
The sealed door was ugly, old, and far too intact. It stood at the end of the corridor like a slab of dark metal hammered into the hive's bones. The mutants had swarmed around it. Died around it. Guarded it without understanding why.
Grot strode toward it, hoisted his gravitic hammer, and swung.
The impact cracked the air. Dust burst from the surrounding wall. A tremor ran through the floor hard enough to make the nearby soldiers stagger.
The door did not move.
Grot stared.
"…Huh?"
He stepped back, rolled his shoulders, and set himself in a charging stance. His jump pack ignited with a hungry roar. Heat blasted across the corridor as he launched forward like a human battering ram.
His shoulder hit first.
For the first time since becoming Thunderborn, Grot felt real resistance.
The impact should have torn the door from its frame. It should have shattered hinges, buckled locks, or at least dented the surface. Instead, the shock ran outward. The wall around the frame cracked. Ferrocrete split. Old reinforcement bars twisted free. Dust and masonry collapsed in heavy chunks around the door.
The door remained standing.
Grot activated his gravitic shield and leaned into it, trying to crush the obstruction through brute force and directed pressure. The surrounding wall gave up before the door did. A whole section of corridor collapsed inward with a grinding shriek of metal and stone.
The door still stood there, untouched and faintly insulting.
"…The hell?"
Grot looked at the open gap where the wall had been. Then he looked back at the door.
After a long pause, he shrugged.
"Fine. Be like that."
He walked around it.
Inside the Chamber
The room beyond was silent.
No mutants waited inside. No ambush triggered. No hidden brood-nest burst from the walls. Nothing moved except dust drifting through the air in pale sheets where Grot's violent entrance had disturbed it.
The chamber was unexpectedly intact. Its walls were old but clean compared to the corridor outside, protected by the same unnatural resilience that had preserved the door. The air smelled stale, sealed, and faintly sterile beneath the heavier stink of battle spilling in from outside. Broken lumen-strips glowed along the ceiling, their weak light pooling around a single bed placed at the center of the room.
On the bed lay a woman.
Blonde. Unconscious. Human.
That last detail struck Grot harder than the door had.
She did not look like anyone who belonged in the Underhive. Her features were unmarked by hive-rot, rad-scarring, malnutrition, sump-sickness, gang brands, or the thousand small injuries that life below the manufactoria carved into human beings. Her skin held a clear, almost luminous quality beneath the chamber's pallid light. Her expression was calm, too calm for someone found behind a wall of mutants and corpses.
She wore an Imperial uniform, but it hung wrong on her. The cut was military, the fabric torn and stained, yet the fit suggested it had not been made for her. No ident-tags. No unit markings that matched local records. No rank pins. No gang sigils. No obvious weapon.
Just a woman in a sealed room the enemy had guarded to the death.
Grot's HUD scanners activated at once. Targeting brackets flickered over her body, then shifted into diagnostic overlays.
[Skeletal structure: Human standard.]
[Bio-signs: Stable.]
[Major mutation markers: None detected.]
[Classification: HUMAN, UNMODIFIED.]
Grot exhaled.
"...By the Emperor. What the hell is this?"
The officer who had followed him into the chamber lowered his lasgun slowly. He removed his jacket and draped it over the woman with unexpected care. His face had gone strange: wary, yes, but also softened by an instinct he did not seem to understand himself.
"I don't know who she is," he murmured. "But I think we should get her somewhere safe."
Grot looked from him to the woman.
The right call, obviously. The Lord Commander could ask the difficult questions later. Grot's job was simpler: find survivors, kill threats, don't overthink sealed mystery rooms until someone smarter got annoyed enough to explain them.
He nodded.
"Agreed."
He lifted the woman carefully despite the size of his armor, supporting her weight with one arm rather than tossing her over his shoulder like a sack of ammunition. Even Grot understood that unconscious civilians tended to break if handled like battlefield salvage.
Outside, combat drones hovered overhead, lenses sweeping the corridor and chamber in disciplined arcs. The infantry formed around him without being ordered, nervous now for a different reason. They had expected a monster. Instead they had found a woman too clean for the Underhive, asleep behind a door that ignored a Thunderborn hammer.
That was not reassuring.
Grot carried her out of the bunker and loaded her onto the waiting transport. The drones tightened their formation around the vehicle as it lifted away, ensuring absolute security until the woman could be delivered to the fortress.
....
Fortress, Hours Later
"We don't know her identity. No ident-tags. No gang sigils. No recognizable regiment markings. She was unconscious when we recovered her."
The garrison soldier spoke quickly as he escorted Qin Mo through the fortress corridors, though not carelessly. The man had learned the difference. Qin Mo hated wasted words, but he hated missing information more.
"I would not normally disturb your research, Lord Commander, but I believe you should be made aware of this."
Qin Mo said nothing at first.
The fortress around them hummed with controlled activity. Armored doors opened and sealed in quiet sequence. Logistics drones drifted through side corridors carrying tools, ration crates, medical supplies, and replacement weapon components. Soldiers stepped aside as Qin Mo passed, saluting with the stiff urgency of men who knew the person walking by them was the reason they were alive.
They arrived at a reinforced chamber once used by Laun.
The room had been stripped of its worst noble excesses after Qin Mo took control, but traces remained: smoother wall panels, better insulation, a private water line, and furniture that had clearly never been intended for ordinary soldiers. It was austere by spire standards and luxurious by Underhive standards, which meant Qin Mo already disliked it.
A guard stood outside the door. He saluted and stepped aside.
Qin Mo entered.
Inside the RoomnThe woman was awake.
She sat on the bed with the borrowed jacket around her shoulders. A military officer stood beside her, offering a glass of relatively clean water with both hands. The officer's posture was careful, almost reverent, and that was the first thing Qin Mo noticed.
Not her beauty. Not the strange door. Not the impossible cleanliness of someone found in the Underhive.
The officer. The moment Qin Mo stepped inside, the man straightened and snapped into a flawless Aquila salute.
"Lord Commander. She just woke up."
"Leave us."
The officer obeyed immediately. Yet as he exited, his eyes flicked back toward the woman with an odd reluctance, as though abandoning her in the room with Qin Mo required moral effort.
The door sealed behind him.
Qin Mo narrowed his eyes.
These were not fresh recruits. The fortress garrison had butchered xenos, burned heretics, and watched men die in ways no sane mind should preserve. They respected strength. They respected command. They did not become soft because an unknown woman smiled at them.
Unless something was pushing them.
His attention settled on her fully.
She met his gaze without fear. That was the second warning.
A normal civilian, rescued from a sealed chamber beneath a mutant nest, would have been confused, terrified, grateful, angry, or some messy combination of all four. This woman sat as if the room had been prepared for her. As if the fortress, the guards, the war, and Qin Mo himself were all details in a larger conversation she had expected to happen eventually.
Qin Mo pulled a chair across the floor and sat in front of her.
He could feel it now.
A pressure. Subtle. Polished. Not the open, clawing intrusion of hostile warp filth, but a faint emotional gravity that made attention want to settle on her. It brushed against the minds of others and encouraged trust, admiration, protectiveness. The effect slid off Qin Mo like rain off armored glass, but he recognized the shape of it well enough.
She was a psyker.
Possibly a trained one. Definitely an unregistered one, unless the Imperium had somehow misplaced the paperwork for a woman guarded by mutants behind an indestructible door.
There was no immediate hostility in her expression.
That did not make her safe.
"You're a psyker," Qin Mo said. His voice was calm, cold, and completely stripped of courtesy. "Unregistered, I presume. That makes you dangerous. Civilians are a rare sight in the Underhive, especially behind a sealed door guarded by a mutant pack. Were you part of a gang? A bounty hunter? A cult asset? Or something else?"
The woman's lips curved slightly.
It was not quite a smile. More the acknowledgment of a move made on a gameboard.
"You may call me Vanessa."
She evaded the question entirely.
Qin Mo's expression darkened.
"That was not what I asked."
Vanessa lowered the glass of water to her lap. Her hands were steady. Too steady.
"No," she said softly. "It was not."
Qin Mo leaned forward. The chair gave a quiet metallic creak beneath his weight.
"Then answer properly."
For the first time, Vanessa's gaze sharpened. She studied him not like a prisoner studying a captor, but like someone confirming a theory. Qin Mo felt the faint psychic pressure shift, testing the edges of his mood, looking for fear, vanity, guilt, anger, anything it could touch.
It found nothing useful.
Her smile became a little more genuine.
"You've led an army that should have been annihilated."
Qin Mo went still.
"You've fought against impossible odds and endured."
The room seemed to tighten around the words.
Vanessa tilted her head, blonde hair falling lightly against the borrowed jacket. Her voice remained gentle, almost approving.
"Well done… prisoner."
A cold silence followed.
In an instant, Qin Mo's hand shot forward and clamped around her throat. The chair behind him toppled backward and struck the floor with a sharp clang.
Vanessa's eyes widened. Her calm shattered at last.
Qin Mo lifted her slightly from the bed, not enough to break her neck, but enough to make the limits of the conversation clear. His voice dropped to a low, lethal murmur.
"How do you know who I am? You have three seconds to answer before I burn you to ash."
Vanessa choked. Her hands flew to his wrist, fingers clawing uselessly against armor and inhuman strength. Her feet kicked once against the side of the bed.
"F… from…"
Qin Mo's grip tightened by a fraction.
"Two."
"From your Thunderborn…" Vanessa gasped. Her face flushed, then paled. "The one called Grot…!"
Qin Mo's eyes narrowed.
Grot had spoken too freely, then. Or she had reached into him. Or both. Either possibility was unacceptable.
"Looks like I'll need to prioritize developing an advanced psychic nullifier."
His eyes gleamed coldly. The air around his free hand shimmered with gathering heat.
"Any last words, psyker?"