The Cadian Gate rose before them, a slash of iron will in the starless dark. Even from high orbit, Aurelius could see the geometry of discipline carved into the fortress-world's surface—gun bastions, void-shield grids, trench cities arranged in mathematically perfect arcs aimed into the Eye of Terror. It was not beauty; it was inevitability.
The Phalanx disengaged from translation and hung above Cadia like a golden mountain. Aurelius stood on the observation deck, Seraphine beside him. The null's presence cut the psychic static that bled faintly from the Eye, letting him think in silence.
"Your first steps as a Gate-Warden," she said, voice flat, but the words carried weight.
He inclined his head. "The first stones," he corrected. "The wall itself will take centuries."
Friction at the Fortress
The docking bay of Kasr Kraf was all steel teeth and drilled men. The Cadian High Command greeted them with a reception more suited to political inspection than reinforcement. Their commander, Lord Castellan Draeven, met Aurelius's salute with a frown.
"We've reviewed your 'Myrridian Protocol,'" Draeven began, voice edged. "Impressive, but Cadia is not some fringe world. Our drill and doctrine are older than your service record."
Aurelius did not blink. "Then they will stand if tested. But the Eye will send what Myrridian faced—and more. Your men deserve tools that meet that truth."
Draeven's lips thinned. The debate might have spiraled, but a voice cut through—Mechanicus Cant Binary over the vox-link, summoning Aurelius to the pylon grid survey. The Castellan granted him leave with the barest of nods.
Beneath the Pylons
The Cadian pylons were not merely walls; they were keystones in a lattice that gnawed at the warp itself. Seraphine moved through their shadow like a wraith, her null aura making the air feel dry and sharp. The Mechanicus magi recited liturgies as they scanned for sub-surface anomalies.
Then, at the seventh pylon site, Seraphine stopped.
"Something here," she said. Her null-field flared—Aurelius felt the skin-prickle as the air deadened further.
A pulse of Observation Haki slid down into the rock strata. He found it: a hollow, geometrically perfect, lined with a material his senses could not pierce. It was colder than the void.
The overseeing magos began chanting faster, data-logs stuttering with static. "Blackstone," he rasped at last, mechadendrites twitching. "But this configuration… not of the Imperium. Pre-human. The machine-spirits resist interface."
Aurelius crouched, placing his gauntlet against the soil. "Then the wall we build may already have a hidden foundation."
Drill to Blood
Three days later, Aurelius stood on the bastion line with Cadian regiments arrayed for a coordinated defense drill—his first attempt to graft Walls That Learn onto fortress warfare. Observation pulses rolled off him in steady waves, mapping every squad's readiness, every weak joint in the lines.
Halfway through the simulation, the Eye blinked. Warp-tainted crimson bled across the sky. Alarms shrieked.
"Real contact," Draeven snapped over the command net, disbelief fading into cold focus.
Chaos reaver ships were burning through the outer void-screen, their landing craft diving for the construction sites. The drill dissolved into live war in the span of breaths.
The First Push
The reavers didn't just hit the bastion—they struck everywhere. Pylon sites came under rocket bombardment. Cultist cells, dormant for years, ignited inside trench habs. One landing claw slammed into the partially-complete Gate Anchor, disgorging traitor marines in crimson and brass.
Aurelius moved. His mind split along trained lines:
Pulse Observation — bursts of foresight mapped enemy vectors, marking where artillery should fire before the foe even emerged.
Scalpel Conqueror's — short, precise bursts that steadied green regiments, freezing panic before it could bloom.
He locked eyes with a young Cadian lieutenant, voice a low thunder. "Hold that pylon. Not for the Emperor. For Cadia." The man's will surged like a lit fuse.
Counter in the Storm
Seraphine's null aura became their knife in the dark. She ghosted through breach corridors, the warp-light flickering where she passed. Daemons winked out like snuffed candles when they came too close.
At the Gate Anchor, Aurelius met the enemy commander—a hulking Chaos Champion draped in flayed banners. Their duel was a clash of titans, spear against daemonblade, gold against rusted ruin.
The Champion's strikes carried warp-weight, bending reality with each blow. Aurelius bled energy through his Haki, Observation seeing half-breaths ahead, Conqueror's flaring each time Cadian squads began to break under the sight of the monster.
Then, a gap. One heartbeat of overreach. Aurelius's spear took the traitor through the gorget, and the shockwave of his will rippled out, shattering the raiders' coordination.
Aftermath and Omen
By nightfall, the bastions still stood. Pylon construction crews returned under guard. The reavers fled back into the warp, leaving only burning husks in the snow.
In the command chamber, Draeven inclined his head. "Your methods… work," he admitted. "Cadia will adapt."
A sealed Mechanicus data-slate awaited Aurelius in his quarters. The magos's voice crackled through a secure channel:
"Analysis complete. The blackstone matrix beneath the pylons predates the Imperium. Its geometry does not match known human or xenos patterns. Probability of intentional warp-resonance: 97%. Recommendation: Discretion. And vigilance."
Aurelius looked toward the Eye's storm-torn horizon. The wall would rise. But something older than Chaos was already watching the Gate.