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

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The will of the corpse upon the Throne reached Sanguinius through the vocalizer.

But it was no brief greeting. The information itself was anything but sparse. Even as the words came through the speaker, the Emperor was simultaneously pouring vast knowledge into his son through psychic means, just as he had when they first met on Baal.

Through that communion, Sanguinius learned the shape of the age.

An Imperium that had endured ten thousand years since the Horus Heresy.

That was only the broad background. When the Great Angel learned he had been resurrected from death, and learned of Lupercal's return and Guilliman's awakening, composure left him entirely.

"Horus. He came back?"

Sanguinius made no effort to hide what he felt. Kallen, listening, caught nothing in that voice resembling fear or hatred. What he heard was pure joy. Pure relief.

Even with the wound the Warmaster had punched through his chest still raw. Even though moments ago he had been drowning in the despair aboard the Vengeful Spirit. The moment he learned that his once-inseparable brother had reclaimed himself, the weight on Sanguinius's heart finally, completely, lifted.

When you thought about it, this made sense. People often said the closest pair in Warhammer was Ferrus Manus and Fulgrim, but Sanguinius and Horus had been exceptionally close friends in their own right.

The End and the Death trilogy could almost be read as Sanguinius's emotional arc: his boundless grief and regret over the fall of the brother he had once loved.

"Yes, that white Samoyed from Cthonia has returned. Not that big, dumb black wolf who gave me such headaches." A brief pause. "And naturally, today is your father's lucky day. I also received a white swan from Baal."

"Oh, and you must thank Kallen. It was this lad who brought you back."

The Emperor's voice directed itself toward Kallen.

Sanguinius turned.

He looked at the mortal standing before him: an ordinary captain's uniform, no psychic presence whatsoever.

The Great Angel put on no primarch airs. Across that bloodstained and somehow still flawless face, a wholly sincere smile appeared. He even forced his right arm to lift, pressing his palm slowly and deliberately against the shattered armor over his chest.

"Thank you, Mr. Kallen."

The Angel's voice was gentle. Steadying.

"I don't know how I could possibly express my gratitude—"

"Gratitude can wait."

Kallen waved him off.

"Right now I'm going to step outside and get those Custodians in here. You and Loken need to be on stretchers five minutes ago."

"Loken?"

Sanguinius paused. He followed Kallen's gaze to the side.

Only then did he notice, lying in the pool of blood beside his outer thigh, an Astartes in old-style Mark IV white power armor. The Luna Wolves badge on his pauldron was damaged, but still clearly visible.

His nephew.

Sanguinius had never had many private conversations with Garviel Loken, but the Great Angel had always held this warrior in the highest regard.

He still remembered it clearly: on the eve of the Siege of Terra, it had been this remarkable young man who laid the brilliant ambush at the Saturnine Wall, and it was in that same battle that Loken had personally cut down his former brother-in-arms, Little Horus Aximand.

In private, Sanguinius had given him his highest praise: a truly outstanding Luna Wolves warrior, possessed of genuine and uncorrupted honor.

"Mr. Kallen, did Loken also die in battle?"

The Great Angel had already accepted his own resurrection as fact. He was equally curious about his nephew's return. He had once glimpsed Loken fallen in a pool of blood, in fragments of psychic vision, but had never known the exact cause.

"Yeah. That bastard Erebus stabbed him in the back." Kallen said it with complete, unmasked contempt.

At that name, Sanguinius's brow drew tight. A flash of anger crossed his face and was gone.

"Alright, you're the patient here — stop worrying about everyone else." Kallen slapped his knees and rose to his feet. "I'll go outside and get those guards in here to do their jobs."

"I am in your debt, Mr. Kallen." The Great Angel dipped his head once more.

Kallen said nothing else. He turned and walked with long, quick strides toward the towering golden gates.

---

Outside the Throne Room.

On the broad steps of the Sanctum.

Eagle Guard Kalim Varanor stood with both hands folded over the haft of his auramite halberd, gripping it hard. Behind his faceplate, his features had been drawn tight with irritation for some time now.

It had been a while since Guilliman, the suspected-Horus, and that Dark Angel had departed.

Both primarchs and the Astartes had received emergency orders to reinforce the Lion's Gate and left in considerable haste.

But that foul-mouthed mortal was still inside the Throne Room.

Varanor loathed the arrangement. A mortal with no rank, no background, nothing. What gave him the right to remain alone with the Master of Mankind this long? It was a desecration of Holy Terra.

He was still weighing whether to disregard protocol and force the doors open when —

BOOM!

A deep, grinding mechanical sound detonated overhead.

The golden gates, dozens of meters tall, pushed slowly open from the inside. A broad shaft of light poured from within and fell across the steps. Kallen stepped through the gap.

Every gold-armored Custodian went rigid at once. Dozens of superhuman warriors turned in unison, locking their gazes on the mortal.

"You lot, stop standing there like a row of door gods." Kallen stood at the top of the steps and beckoned down at the warriors below. "Get medical personnel here now. And send a few of you in with me — there are two people inside who need stretchers immediately."

Varanor planted a heavy boot on the flagstones and stepped forward. The impact rang flat and hard.

"Mind your tongue, mortal." The Eagle Guard's voice dropped low and cold. "No one else can be inside the Throne Room besides our Lord. Are you mocking His own bodyguard?"

"I said there are two people in there, so there are two people in there. If you don't believe me, go look for yourself."

Kallen couldn't be bothered arguing with these stubborn iron-heads. He simply stepped half-aside and jabbed his thumb toward the open doors.

"Oh, and while you're at it, you all owe me a serious thank-you. I just installed a vocalizer for His Imperial Majesty. He's in there waiting for you right now."

A vocalizer.

Varanor's fingers clenched tight around the halberd haft.

He didn't believe a single word of it. But the security of the Throne Room came before everything else.

He turned and signaled the two Custodians beside him. The three of them leveled their halberds and followed Kallen down the long corridor toward the Throne, each step wound tight with caution.

The further they walked, the colder Varanor's spine became.

Blood. The air was soaked with it, pungent and heavy and unmistakably fresh. A smell that had absolutely no business existing in the most sacred sanctum in the Imperium.

They emerged from the corridor. Their eyes reached the base of the steps.

Varanor's feet stopped.

He could not move another inch.

Behind him, the two Custodians let out sharp, involuntary breaths. One man's halberd butt rang off his own armor plate.

There, at the very bottom of the stairway leading to the Golden Throne.

In a vast pool of still-liquid blood, sat an enormous figure.

Long golden hair darkened to crimson by gore. The great white wings on his back, his signature, his mark, were tattered and broken. His body was covered in wounds that should have been fatal. He looked as though breathing itself might stop at any moment.

And yet.

That perfection, written into the very sequence of his genes. That unparalleled magnificence that made every Astartes, every Custodian, feel an instinctive and bone-deep urge to kneel.

In the entire galaxy, there was only one.

Lord of Baal. Gene-sire of the Ninth Legion. The Great Angel.

Sanguinius.

"This... this cannot be possible..."

Varanor's lips trembled beneath his faceplate. The cold Custodian commander's voice could barely hold itself into coherent words. His mind had gone completely blank.

"What do you mean possible or impossible?! Get him to the medicae ward, now!"

A rough, furious voice crashed down from above. Varanor's entire body flinched. He snapped his head up toward the Golden Throne at the summit.

"My Lord... is that you?" He could barely hold his halberd steady. Disbelief cracked through every syllable.

"Obviously! Of course it's me! Your creator! Now get my son and Loken to the healers, or I will come down there and kiss your backsides with my own feet! And then bring me Constantin Valdor!"

The Emperor's command came out in a tone bordering on mania.

And yet it brought all three of them to tears. After all this time, they could finally hear their Emperor speak. Even through a vocalizer. Even like this.

"Yes! My Lord!"

Varanor turned to the Custodian behind him and signaled for reinforcements from outside, then looked back up at the Throne. If he could, he would have stayed there forever, just listening, even in a tone like that.

"My Lord, the previous Captain-General, Lord Constantin Valdor, has long since departed. The current Captain-General is Trajann Valoris. He is presently commanding the defense of the Eternity Wall."

"Then summon him to me when the war is over."

"Your will be done!"

More Custodians flooded into the Throne Room shortly after.

When they saw Sanguinius, alive, and heard the Emperor speak, every one of them froze. The Ecclesiarchy bishops who normally lorded over everyone would have fainted dead on the spot.

"Level the stretchers! Gentle movements! Can you manage a little tenderness for critically wounded patients?!" Kallen had appointed himself on-site commander.

Several Custodians, moving with trembling reverence, eased the unconscious Loken and the weakened Sanguinius onto anti-grav stretchers.

As the Great Angel was lifted, he endured the pain and gave Kallen a small, deliberate nod.

Then Sanguinius turned his head and looked up at the Throne above, a long and wordless look.

He said nothing more. But that bond between father and son, spanning life and death and ten thousand years, was reforged completely in that moment.

The medicae team carried both wounded away under heavy Custodian escort, departing in haste. The once-crowded Throne Room emptied in an instant.

Kallen stretched his whole body with a long, lazy groan, his bones cracking and popping. This trip to Terra, he had decided, was somehow more exhausting than actual combat.

He dusted off his trouser legs and turned to follow them out. Find some air. Find a corner. Breathe.

"Don't go anywhere yet, Kallen."

The Emperor's voice came from behind without warning and pinned him where he stood. "There is one more matter I need to entrust to you."

"Huh?" Kallen turned. "What else? The battle out there is a disaster. You're not sending me to help with that — so what exactly are you keeping me here for?"

Silence on the Throne. 2 full seconds.

A slow, deep exhale came through the vocalizer.

"I need you to retrieve another of my sons."

Kallen raised an eyebrow. "Who?"

"The VIII Legion. Gene-sire of the Night Lords." The Emperor enunciated each word with deliberate weight. "Konrad Curze."

Kallen's pupils went wide.

He stared at the withered corpse on the Throne, and the words came out at full volume before he could stop them.

"Are you fucking insane?! You want me to drag back that psychotic flying rat?!"

---

(Author's note: According to the Black Library novels, it is explicitly stated that the assassin from the Officio Assassinorum cut off Konrad Curze's head and returned with it as proof of the kill. That said, I'm not entirely convinced that a Curze who never fell to Chaos has zero path back, and given a primarch's nature, the author has chosen to treat the question of whether he actually died as unresolved, using that ambiguity as the entry point. As for his role going forward, the plan is for him to operate in the shadows for Guilliman, quietly eliminating those who refuse to fall in line.)

➤ Next: The Emperor's Compensation

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