Warhammer 40K: System Error, I Summoned the Arch-Traitor!

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War was never just a collision of gunfire and blood. It was precise political surgery.

Horus stared at the star chart, his finger tracing slowly along the border of the T'au Empire.

He understood what this war meant. Not conquest. Not destruction. A slap, loud but not fatal, painful yet bearable.

The goal was to force the T'au Empire back to the negotiating table and make them sign the treaty Ultramar had laid down.

"Swift assault, decapitate the command, besiege the strongpoint and hit the reinforcements." Horus addressed his senior officers, fingertip resting on the T'au capital world. "We are not equipped for a protracted war. The fleet's logistics won't hold."

He paused.

"Teach them a lesson they will never forget. But don't tear their faces off. The force between those two things — that we have to gauge ourselves."

The words came easily. Every general in the room knew it was ten times harder than simple annihilation.

The combined Indomitus Crusade fleet was assembled and ready.

Five battle groups. Ten full-strength Primaris Chapters, three of them Ultramarines successors personally assigned by Guilliman, the rest drawn from several Astra Militarum regiments.

Konrad Curze was given a mixed special company: stealth and reconnaissance elites, every last one of them. His mission was to seed terror behind enemy lines and churn the T'au supply network into chaos. The Lord of the Night had nothing to say about it. He was never cut out for command anyway. He took Horus's orders, turned, and left.

The frontal battlefield belonged to the Wolf of the Herd.

The core of the battle plan came down to two words: Decapitation Strike.

Pierce the defensive line. Destroy the command echelon. Take the supreme commander alive.

That last part nearly drew formal opposition from the embedded Inquisitor. The radical faction held that no mercy was owed to xenos, that taking prisoners at all was a defilement of the Imperium's purity.

Horus listened to the man's discontent without interruption. Then he addressed it in a handful of sentences. His voice never rose, but each word landed precisely at the border between the Inquisitor's faith and his reason. In the end, the man nodded and went quiet.

This was the Wolf of the Herd.

He could command armies across the stars and grind enemies to dust. He could also sit across a table from the most stubborn opponent alive and walk away with their signature.

The mission of taking the enemy commander alive, he would personally place in the hands of the son he trusted most.

"Loken."

In the armory, Garviel Loken bowed his head as his Gene-Sire entered.

Horus had pulled nearly every Terminator from all ten Chapters and rebuilt them into a single iron fist under Loken's command. Their bloodlines were different. At that moment it didn't show. They stood in uniform rows, still as statues cast from steel.

"It has something of the old Justaerin about it." Horus looked across the assembled force, and something flickered in his eyes, old and distant. He reached out and clapped Loken on the shoulder guard. "From this moment, you are First Captain of this Terminator force."

Then he smiled. A father's smile, laced with gentle teasing. But underneath it, barely visible, was something else.

"Loken — if Ezekyle were still at my side, he would envy you. You've taken the glory that was supposed to be his."

Loken raised his head. His gaze was steady and clear, the same as it had always been.

"With respect, my Wolf. I don't care for glory. Only for the mission you give me. To act under your command again — that is the only wish I have left."

He paused. His voice dropped.

"Ezekyle... he has lost himself."

The words landed like a stone dropped into still water. Legion-era memories rose with them, faces that had stood shoulder to shoulder with him, bonds that had dissolved into the shadow of the Heresy long ago. A trace of grief moved through Loken's eyes.

Horus said nothing.

He placed his hand on Loken's shoulder guard and pressed down. Hard.

"If you are in danger," the Wolf of the Herd said, his voice dropping low, meant for Loken alone, "I will come down and pull you out myself. The same as on 63-19."

63-19.

The number was a key. It unlocked something in both of them at once.

The smile at the corner of Horus's mouth went still. Slowly, it turned bitter.

"I will not make the same mistake again," he said. "I will not send my sons to negotiate with unknown forces without warning. Sejanus died because of me."

Loken looked at his father.

"But I remember your strength on that world, my Wolf." His voice was steady and warm. "You saved me. The day you killed that Emperor."

He drew a breath and spoke words he had spoken more times than he could count.

"I was there."

He couldn't recall how many times he'd said it. Usually it came out under Torgaddon's relentless coaxing, delivered to whoever was willing to listen.

Because it was glory he had witnessed with his own eyes.

But now, as the words left his mouth again, a chill moved through him.

He had just realized what it was.

A dress rehearsal.

The 63-19 system had nine planets, the same as the Throneworld. The ruler of that sealed system had proclaimed himself Master of Mankind and crowned himself Emperor. And his father had personally executed that false Emperor.

The image was still engraved in Loken's memory: the dome of the golden palace crumbling under bombardment, Horus striding over the wreckage of men who had called themselves Custodes, cutting down the pretender.

Horus did not want to revisit it. The war had been won. The cost had been too high. That was his shame.

"Enough." Horus drew himself back and fixed his gaze on Loken. "Prepare yourself. Complete the mission. If there is any difficulty, "

"I will tell you at once."

"Good." Horus nodded and stepped back. "Now, let those xenos learn what it means to face a Luna Wolf. What it means to face the Imperium of Man."

Loken drove his right fist into his breastplate.

"Your will, my lord!"

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The Agrellan Gulf was composed of several worlds. The most important was Prefectia.

It was one of the critical strongholds the T'au Empire had seized during the Third Sphere Expansion. The Gulf controlled the shipping lanes into the Dovar System, and the T'au valued it accordingly.

Their original gateway world, Agrellan itself, had once been a fine location. The Imperium had erased it with Exterminatus during the Second War, leaving the T'au no choice but to redirect their energy and resources to other captured worlds.

What they did not know was that something had already slipped into their backyard.

Curze brought Sevatar. Father and son led a fleet small enough to hide in the shadow of an asteroid, driving it like a poisoned needle, silent and soundless, deep into the Agrellan Gulf.

Their operatives worked into the key nodes of every planet in the system. Right under T'au noses they planted timed charges, sabotaged comm towers, and corrupted data networks.

Their tradecraft was so clean that even the most alert T'au sentries noticed nothing.

At first, the garrisons assumed local vermin were gnawing at the cables.

Earth Caste maintenance teams were sent out in waves to find the faults.

Not one wave came back.

Search teams eventually found them in an abandoned pipeline.

The Earth Caste engineers had been hollowed out. Their bodies were impaled in neat rows on iron railings, like twisted road markers. Every single one's eyes were open, pupils frozen with the terror of the last second of their lives.

Members of the search teams broke down on the spot. These young T'au soldiers had never encountered anything like it. This wasn't killing. It was a message.

The moment the bodies were brought back to garrison, fear spread through the rank and file like a plague. No one could stop murmuring. Everyone started checking the darkness at their backs a second time.

Then Horus's main fleet appeared at the edge of the system.

That was when Curze's symphony of terror hit its crescendo.

Every night, someone was dragged into the darkness. Every morning, the body appeared at the highest point of the garrison, strung up and displayed, like banners stitched from flesh and blood.

Across the comm channels, screams for help and the dying cries of kin played in an unbroken loop, day and night. No one could shut it off. No one could cut the feed. It was as if the deepest nightmare buried in every T'au had been dug up and screamed back into their faces on repeat.

Fear ate through the command structure.

When the first artillery salvo lit up the sky over Prefectia, Horus's army came.

➤ Next: Interrogating the Daemonhost

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