The Thunderhawk's descent shook with the atmospheric turbulence of Caltrius. Aurelius stood motionless in the troop bay, the crimson and gold of his armor freshly re-polished from his return to Terra. The briefing from the Captain-General still burned in his mind — not orders, not instructions, but the weight of expectation. The Emperor had looked into his soul and found… something worth watching.
The Custodian's hand tightened on the haft of his guardian spear.
The Emperor's words still echoed.
"You will return. You will endure. And you will see what lies beneath."
The city of Caltrius spread out below, its outer districts still scarred from the purges weeks earlier. The cults were broken on the surface — so the Imperial reports claimed — but in the tunnels, in the deep catacombs, the corruption festered. And now, reconnaissance vox-logs told of power armor glimpsed in the dark. Old armor. Baroque. Markings that did not belong to any loyalist Legion.
The ramp dropped with a hiss of hydraulics. Aurelius stepped into the ash-thick air, his optics scanning over the waiting Imperial Guard officers. Their salutes were crisp but their eyes carried the tremor of men who had seen.
"Lord Custodian," the senior officer — Colonel Vethren — began. "We've cordoned the main streets. The cult remnants have been forced below. But… we've lost three patrols in the lower sectors. No bodies recovered. Only blood trails."
Aurelius didn't waste words. "Take me to the last breach."
The breach was a collapsed chapel, its marble altar shattered into rubble, the air beneath reeking of machine oil and old blood. Guard squads fanned out around him, lasguns at the ready. The descent into the catacombs was a spiral of stone steps slick with moisture, the vox interference growing thicker with every meter.
He could feel it before he saw it.
Observation Haki brushed out from him like ripples in a black ocean — searching, tasting the air of intent. And there it was:
A cluster of presences, too steady, too cold for mortal men.
And one, far deeper, like a blade pressed against the back of his skull.
They were waiting.
The ambush hit with bolter fire that chewed the stone walls to dust. Aurelius moved before thought — spear flashing, Haki-flared movements predicting the arcs of incoming fire before they landed. Guard troopers fell behind him, shredded, but enough survived to lay down a retaliatory volley.
The enemy stepped from the dark: six Chaos Space Marines, armor pitted and etched with blasphemies, their bolters roaring. But they were not the leader. Aurelius could feel the leader watching from deeper within the tunnels.
The fight was brutal. Armament Haki flowed over Aurelius's armor in a black-gold sheen, bolter shells sparking harmlessly off where mortal ceramite would have cracked. His spear struck like lightning, severing limbs, shattering helms. Yet each kill burned his reserves — Haki demanded will, and here in the dark, the Warp pushed back against him with every heartbeat.
By the time the last Marine fell, the Guard squads were reduced to half-strength.
"Colonel," Aurelius said, voice low. "Collapse this level behind us. Force them into the lower vaults. We finish this now."
They advanced deeper, through halls where the air seemed to bend, where whispers clawed at the edge of thought. Aurelius's Conqueror's Haki rolled outward — not in a roar, but a cold, suffocating pressure that pushed back the Warp's whispers. Guardsmen found their breath again. Hands stopped shaking.
At the vault door, the leader emerged.
The Chaos Lord was a giant in blackened Mark III plate, a chainfist dripping ichor, and a helm wrought into a snarling beast's visage. His voice was a bass growl over the vox.
"A golden lapdog. The Throne sends you to die in the dark."
Aurelius didn't answer with words. He answered with motion.
The duel was a storm — chainfist against guardian spear, warp-tainted strength against the Emperor's perfect blade. Aurelius's Observation Haki stretched to its limit, reading each murderous arc, but the Lord was relentless. The Custodian shifted into a blend of spear and empty-hand strikes, using Haki to drive force through armor gaps.
The killing blow came as the vault began to collapse — Aurelius stepping inside the chainfist's guard, Armament Haki flooding his gauntlet, driving it into the Lord's helm with enough force to shatter plasteel. The giant fell, the air filling with the sound of the structure giving way.
Hours later, in the burning light of the surface, Aurelius stood with the survivors. The vault was sealed beneath tons of rubble. Whatever the warband had been trying to awaken was now entombed.
And yet…
For the first time, Aurelius felt the weight in his limbs. The exhaustion that even his Custodian frame couldn't entirely banish. And in the quiet, a thought:
How many more times can I do this?
It was the first seed of doubt. And the first time he wondered if the Emperor had chosen him not just to fight — but to endure.