"Custodian," said the senior among them. Not a Primarch—Rogal Dorn's presence would have crushed the deckplates—but a man molded by him. Captain Evander Kall, Blade-Command adjutant. His features were hewn; his voice was a verdict. "The Sigillite's messenger spoke highly of your… outcomes."
Aurelius inclined his head. "Outcomes are what survive intent."
Kall's mouth didn't quite move, the Fists' version of a smirk. His helm mag-locked to his waist. His eye-line shifted past Aurelius to Seraphine and stayed there a fraction too long. Librarians by the far table grew still in a way that admitted discomfort and refused to display it. The air tugged at their skin as her aura made nearby warp-noise think better of existing.
"Silent Sister," Kall acknowledged, the words arranged like stones. "You'll be… unsettling to certain departments. Entirely acceptable."
Seraphine answered with a small sign at her hip: Acknowledged. No voice to disturb. No thought permitted passage. The nearest Librarian's knuckles whitened on a staff; he relaxed only when she looked away.
Kall gestured to the hololith. Void-siege schematics unfurled: layered arcs of fire, pressure doors mapped like arteries, boarding lanes simulated as red threads through the ship's black. "We are to test this 'Myrridian Protocol.'"
"It isn't a doctrine," Aurelius said. "It's a posture. Walls that learn. Guns that behave as if tomorrow matters. Men who are allowed the dignity of doing one thing well at the moment it matters."
"Poetry," a junior captain muttered—only almost under his breath.
"Work," Aurelius corrected, as if adjusting a weapon's sight.
Kall's gaze measured him. Then: "Very well. Wargame parameters are set. You will command three decks against rotating assaults. We will pressure you with deception."
Aurelius turned to Seraphine. She lifted two fingers: Ready. He faced Kall again. "Begin."
At first, the exercise was exactly that: clean enemies behaving like paid actors. Boarding beacons strobed in false red; drill-crews stormed through hatches with blank-muzzle bolters. Aurelius ignored the spectacle. He walked the decks like a carpenter reading grain, set squads where his pulses of Observation told him enemy mass would arrive, and treated the wall as a living unit. Conqueror's Haki went out in scalpel-bursts keyed to timings he spoke in clipped, mathematical syllables.
"Hold breath now. Fire now. Shift one pace left. Brace on my count: three, two, take."
The Fists responded the way stone responds when properly chiseled: as if the sculptor had only revealed what was already there. Kill zones refocused in heartbeats instead of minutes. Rotating assault patterns broke on men whose hands no longer shook at the pivot. Librarians reported "reduced cognitive tremors in squads under gold influence," their own minds prickling where Seraphine walked.
Kall watched without praise. Praise wastes training. He turned dials with his officers, layering feints into pressure and pressure into floods. Aurelius let each layer show its teeth before he filed them down. He saved men not by catching bullets but by ensuring the bullets arrived at polite angles and were greeted by steel that had remembered to exist at the right height.
"Interesting," Kall said once, which in his dialect meant useful.
It almost felt like a lesson until the alarms changed.
The sound stiffened spines first, then sharpened eyes. Exercise klaxons were broad and theatrical. This tone was thin and mean—real. A second later, the Strategium's holo spiked itself with angry red notches in places no drill had scheduled. Internal blast-doors cut; void shutters jammed; two magazine lifts blinked from amber to seized.
"Status," Kall snapped, and voices came back clipped and wrong:
"Deck Thirteen—breach at Saint's Aisle. Drill crew—no—hostile—"
"Magline Delta compromised internally—friend-foe codes spoofed—"
"Section Vox dead from inside—"
Aurelius didn't waste a heartbeat being surprised. Seraphine's fingers flicked a sign: Stealth hex. Her expression didn't change; the skin tightened at the corners of Librarian mouths as they felt something slip past the edges of thought.
"Alpha," Kall breathed. Not fear. Recognition. Hydra's work.
Aurelius's spear clicked into his palm as if it had been waiting there all along. "Captain," he said, already moving, "your men hold the magazines. Seraphine with me." He didn't look back to see if she followed. She would. The Librarians made space for her the way one makes space for a blade descending, and were honest enough to look relieved when her field washed past.
Kall's orders snapped through vox like rivets slamming home. "Third and Ninth to Magline Delta. Librarius to net restoration. No unnecessary heroics. The hydra eats fools."
They hit Deck Thirteen at a run. Lights strobed seizure-white, turning corridor paint into binary code. Servitors tried to apologize for dying by continuing to work. Drill-crew uniforms spotted the floor, discarded where strangers had been wearing them. Alpha Legionnaires moved through the smoke like ideas that wanted to be true.
They saw Seraphine first and flinched—for a heartbeat their stolen hex-fields hiccuped and dropped like liars caught mid-sentence. Aurelius spent that heartbeat without pity. Observation pulsed—short, clean cones down intersecting corridors, intent lines drawn as if by a drafter's pen. A bolt round came at his face from the left; his head wasn't there. The return thrust put a traitor against a bulkhead hard enough to make it choose a different occupation. Another came high with a chainblade; Aurelius used the man's momentum to introduce him to the deck. Conqueror's tapped a third in the will and made his next breath late; a Fists breacher, orange muzzle-flash painting his visor, used the lateness to end him.
"Hydra cells splitting to two targets," a sergeant voxed, voice steady because there was gold at his back. "One for the magazine, one for the macrocannon locks."
"Seal the mag," Aurelius said. "I will close the locks."
He did not mean alone. He meant with a wall that has learned.
They cut through a tertiary service trunk that had been designed to be boring. Alpha had made it exciting—tripped the friend-or-foe vox to read all friends and let themselves into places where only engineers and lies should be. Seraphine's field made the vox second-guess its hospitality. Panels flickered to shame. Doors remembered to be doors again.
At the macrocannon housing, armored figures were already splicing command runes like burglars rewriting a will. Seraphine stepped onto the threshold and the runes went flat, as if ink had decided dryness was beneath it. The saboteurs staggered, like men stepping off a curb they hadn't seen in the dark.
Aurelius gave them no time to write new arithmetic. He moved not fast but on time—Observation stacking pulses into a rhythm: see, act, shift, see. He cut elbows and cables, not just throats. He made choices that prevented other choices from happening. A blow he could have taken with Armament he instead redirected into a console that had been about to betray its mother. When the last traitor looked for a retreat written on schematics fifty years out of date, he found Seraphine standing where his exit should have been. He stared as if species had just been invented. She didn't move. He decided not to be alive.
"Locks are ours," the sergeant voxed, breath sandpapered. "Magazine green. Casualties… acceptable." The Fists' version of we paid fairly.
Aurelius exhaled. The breath left him cleaner than it had any right to be. "Captain Kall."
"Report," Kall returned from the Strategium, tone unchanged. It would have been unchanged had the deck inverted.
"Alpha penetration contained. Losses sealed. Recommend audit of drill rosters. Someone wrote their names in pencil."
"Agreed." A pause. Then, the smallest thread of something like satisfaction. "Your posture holds."
"It learns," Aurelius said.
Debrief filled the Strategium like a low tide, revealing rock. Kill-cam ghosts of the fight rewound and stopped at Kall's index flick. Blade-Command officers asked questions that were knives turned sideways to test for flex. Librarians spoke sparingly; none met Seraphine's eyes for long. She did not require thanks to continue being indispensable.
"We are adopting three elements immediately," Kall said at last. "Pulse pre-aiming keyed to deck geometry. Brace-bursts timed to shield rotations, not the panicked rhythm of human fear. And decentralized intent relays—your… influence—distributed through chosen sergeants to reduce single-point failure."
"Intent is not a resource you can plumb with pipes," a junior captain objected, almost respectfully.
"Then shape men until it becomes one," Kall replied, and no one felt that he had been cruel.
Aurelius neither bowed nor basked. He made mental notes where gratitude might have been. He watched how quickly the Fists absorbed useful humiliation, how few words they spent on praise, how the room's angles felt like Dorn's patience may have been here an hour ago and had left fingerprints.
A runner in fortress livery entered at a controlled pace that admitted urgency only to those trained to see it. He presented a sealed wafer to Kall and to Aurelius both. The sigil on the wax was sun-yellow and black, stamped deep enough to leave a thought: DORN.
Kall broke his first. Read. Looked older by one victory and one task. Nodded to Aurelius.
The Custodian cracked his copy. The words were precise enough to be a blade:
Custodian Aurelius, Silent Sister Kest.
Proceed at once to the Cadian Gate.
Assist in pre-fortification and doctrinal consolidation.
The Gate will require men who teach walls to learn.
— Rogal Dorn, Praetorian of Terra
The hololith shifted to a new star-map at Kall's gesture. The Eye of Terror was not yet a roar; it was a wound that had learned to inhale. Cadia's pinprick burned like a candle cupped against that breath.
"Your next theatre," Kall said.
"Already lost?" Aurelius asked, the echo of Dagon Reach respectful of its place.
"Not if we start now," Kall said. Fist-words. Wall-words. The kind men say when they intend to be old someday and have taught ages to behave.
Seraphine's hand shaped a small question: Go?
"We go," Aurelius said.
The Librarians bowed—some from discipline, some with the blank relief of men who prefer their minds quiet. Blade-Command saluted as one—flat-palmed, sharp, unadorned. Kall offered his hand; Aurelius closed a gauntlet around it. The pressure spoke in their shared tongue: Useful. Come back. Bring the wall with you.
On the gantry overlooking Dock Twelve, shuttles took breath like beasts at harness. Seraphine walked at Aurelius's flank; their auras slipped over one another with the faintest hiss, like two blades passing in a tight scabbard. Below, tech-adepts prayed in binharic to clamps and seals. Above, banners hung unreadable because the future had decided not to be courteous.
Aurelius let Observation pulse once, measuring not threats but work—ship schedules, load lists, the map of a Gate he had never seen and already understood as task, not symbol. He let Conqueror's sit like a weight across his shoulders, not yet asked to be shared, content for this breath to be only his.
"Walls that learn," Seraphine signed, the words neat as cut stone.
"Men that do," Aurelius answered, aloud.
They walked into the hold's light. The Phalanx watched them go with angles that approved. Far ahead, a world of pylons and trenches waited to be told how to exist.