Chapter 423: By the Emperor's Decree! Purge This Place! Run!
Lion agreed with Guilliman's proposal—at such a critical time, the Imperium could not afford internal strife.
As long as the Universal Megacorp didn't act against the Imperium, they absolutely must not be the ones to start a conflict.
"Let's just hope those lunatics in the Adeptus Mechanicus can stay calm and not do something idiotic that drags the entire Imperium down with them," lion sighed.
The relationship between the Adeptus Mechanicus and the Imperium was more akin to a partnership. Even the Emperor himself often struggled to exert full control over them.
After the Megacorp envoy delegation visited Holy Terra, the Mechanicus quickly split into two factions.
One was the "Descent" faction, who believed the Megacorp to be divine saviors sent to uplift humanity—angels come to share technological miracles.
They preached that all mankind should immediately submit to the Megacorp and embrace these gods.
But the opposing faction saw the Megacorp as nothing more than freeloading thieves, here to steal their STC modules and relics from the Golden Age of Humanity.
Such parasites, they argued, should be driven out at once!
Yet regardless of their stance, either faction within the extreme Mechanicus might still end up doing something foolish enough to bring ruin upon the Imperium.
"I've already submitted a report to the Emperor," Mortarion said, a twisted, eager grin spreading beneath his mask.
"I've deployed troops to investigate Prospero—shouldn't take long to get results."
Of course, Mortarion had no interest in finding the actual truth. All he needed was a single Thousand Sons warrior showing signs of flesh-mutation. That would be enough for him to declare the entire legion irredeemable.
Immediate purification required.
As for the possibility of executing innocents? Not his concern. He was simply acting on the Emperor's command.
If there was blame to be assigned, it would fall on the Emperor or Chancellor Malcador—Mortarion would simply be the blade.
His sole mission on Prospero: purge the damned heretics of the Imperium!
"Very well. I'll begin preparations for orbital bombardment," the lion nodded in agreement.
Strictly speaking, lion should have dispatched his own investigation team to verify reports of mutation among the Thousand Sons.
But he had no intention of doing so. He wanted to skip straight to the purification process. End it swiftly and cleanly.
Among all the Primarchs, Magnus was far from popular. His arrogance was such that even Horus would have found him unbearable.
Second only to the Emperor in psychic talent, and in control of vast swathes of Imperial knowledge and archives, Magnus truly believed himself the most intelligent of all the Primarchs.
This inflated ego naturally bred scorn for his brothers.
What enraged the other Primarchs most was Magnus's repeated friction with them during the Great Crusade—he often sought out knowledge from xenos and alien civilizations, clashing openly with his brothers.
He once ordered his Astartes to clash violently with fellow Imperial forces just to defend alien libraries and data vaults.
Or he would deliberately stall during campaigns, resulting in his brothers being drawn into brutal prolonged battles.
Were it not for the Emperor's repeated interventions, Horus would have long since taken the opportunity to gut that arrogant fool.
It's important to remember: the purpose of the Great Crusade was to restore human civilization and eliminate all xenos—including every trace of their cultures and knowledge.
The Imperium was, in essence, an extremist xenophobic entity.
Magnus's actions flew in the face of everything the Imperium stood for, making him a pariah among the Primarchs.
The lion,Russ, Mortarion—none had any fondness for him. Only the good-natured and benevolent Guilliman had any patience left. The others wanted him dead.
"I'll send a proper investigation team to the surface," Guilliman said. "Once we've confirmed the situation, we'll deliver the Emperor's decree."
Guilliman held little hope for saving the Thousand Sons. But at the very least, he didn't want the innocent among them to die without knowing why.
—
—
At that moment, on the surface of Prospero—
"invincible reason, Hrafnknel, Glory of Macragge, Endurance—!"
The warriors of the Thousand Sons had already identified the four flagships of the arriving Primarchs. They knew immediately—something was terribly wrong.
Combined with the Emperor's orders and the Universal Megacorp's sudden quarantine, and the strict command to remain where they were—the senior commanders of the Thousand Sons had a grim realization:
This wasn't just a show of force.
Something devastating was about to happen.
But none of them understood why. What had they done to provoke such an overwhelming response? Why had the Emperor dispatched four Primarchs to Prospero?
A heavy, oppressive dread spread through the heart of every Astartes in the Thousand Sons.
At first, some still hoped it was all a misunderstanding.
But the arrival of four Primarchs left no doubt—blood was about to be spilled.
"What the hell are they trying to do?"
Magister Amon scowled deeply, his gaze fixed on the Imperial fleet in low orbit.
As Magnus's childhood tutor, personal steward, and senior advisor, Amon held tremendous authority on Prospero—he was effectively the legion's second-in-command in Magnus's absence.
"Amon! Guilliman and Mortarion have dispatched investigative teams. Also—this letter arrived. They want you to read it personally!"
Azhek Ahriman rushed in, glancing nervously at the Imperial inspection teams gathering outside. A deep unease gnawed at his heart.
Was this about the flesh mutations that had erupted earlier?
But those had already been cured…
Magnus had sacrificed an eye to heal them, for Throne's sake!
Amon turned to the holoscreen and opened the letter.
As the contents unfolded line by line, a furious storm ignited within him.
"Foolish Magnus… are you truly going to doom the Thousand Sons?!"
Learning the full extent of Magnus's actions—and the Emperor's decree—nearly made Amon faint from rage and despair.
He had once believed Magnus was merely arrogant—flawed, but ultimately clear-headed about right and wrong.
Now it seemed Magnus had become a delusional, unrepentant fool.
The gathered Astartes were stunned by Amon's outburst.
They were shocked to hear him curse their Primarch so openly.
And yet, they were equally outraged—how dare Amon speak that way?
But they knew nothing of what was happening.
All they could do was glare at Amon, waiting—demanding—that he read the letter aloud.
"Magnus has consorted with the foul Gods of the Warp, corrupting Prospero and bringing flesh-mutation upon your legion. He is now lost within the Immaterium."
"The Thousand Sons are beyond saving. By the Emperor's own hand, the order has been given: cleanse this world."
As the final words left his lips, Amon was crushed. He could hardly believe Magnus had committed such crimes.
Now, with the Exterminatus order signed by the Emperor himself, four Primarchs and their legions stood ready to purge Prospero from the stars.
Once the investigation teams confirmed the presence of flesh-mutation, the Imperium's orbital bombardment would commence as scheduled.
All Thousand Sons warriors were ordered to disarm immediately and await judgment by the Imperial fleet. Any resistance would be deemed treason, and all honors and accolades would be stripped away—
Their lives and achievements, reduced to nothing.
The letter wasn't long, but it bore the full weight of the Emperor's signature and Chancellor Malcador's official seal.
Clearly, this was a verdict issued through the proper channels.
When the warriors of the Thousand Sons finished reading the letter with their own eyes, they stood frozen.
Flesh-mutation? An Exterminatus order? The cleansing of Prospero?
This had to be a joke!
"What the hell is this!? There's no Warp corruption on Prospero! Someone's framing us!"
Ankhu Anen roared in fury. As the Grand Librarian of the Thousand Sons, he was intimately familiar with everything that happened on this world.
If a widespread mutation outbreak had occurred, he would have known.
"Utter nonsense."
"We were cured long ago—what mutation? That walking fog-fiend Mortarion must've been high on his own poison fumes and fed lies to the Emperor!"
"This is absurd!"
"…"
Anen's outburst quickly sparked a wave of anger from the other Astartes. The warriors voiced their frustration and disbelief.
They had risked their lives gathering knowledge about psykers for the Imperium, even to the point of becoming estranged from their Primarch brethren.
And this was their reward?
There was no Warp corruption here—they lived on this world! If something was wrong, they'd be the first to know!
Clearly, someone was pulling strings behind the scenes.
The Thousand Sons' senior commanders were furious.
Magnus had vanished, and instead of launching a rescue, the Imperial High Command issued an extermination order against Prospero?
Now they were expected to kneel and accept execution without resistance?
Hadn't they sacrificed enough for the Imperium's psychic knowledge?
Even if they hadn't accomplished much, surely they'd suffered enough. If not contributions, then at least their exhaustion should count for something.
"Magister Amon, we await your orders!"
"That letter is a farce—we can't just accept it!"
"They can't be allowed to slaughter loyal sons of the Imperium!"
A growing storm of voices rallied around Magister Amon, urging him to resist the invading Imperial legions.
Amon took a deep breath, his expression dark:
"We are warriors of the Imperium. We are sworn to obey the Emperor's command."
Those words instantly extinguished the crowd's fervor.
They remembered their vows—before becoming Astartes, they had sworn loyalty to the Emperor.
If the Emperor demanded their death, they had no right to refuse.
But—
"No! There must be some mistake! The Emperor must have been misled by traitors—this is a wrongful order!"
Ankhu Anen stepped forward and snapped, "If we surrender now, we're playing right into their hands! Once the Emperor learns the truth, he will regret this—bitterly!"
Anen remained absolutely loyal to the Emperor. But even so, he refused to accept a death so unjust.
If he was to die for the Emperor, it would not be like this.
Many of the younger Thousand Sons warriors didn't share the same degree of loyalty to the Emperor.
After countless campaigns, the veterans who truly remembered and revered the Emperor had mostly died out.
The younger generation had rarely seen the Emperor, let alone developed any true attachment to him.
To them, the Emperor was little more than a distant symbol—an abstract figure of authority.
Why should they die for someone they barely knew?
This wasn't unique to the Thousand Sons. Similar sentiments could be found in Horus's Luna Wolves as well.
Amon stared hard at the letter on the holoscreen, his jaw clenched, struggling with an agonizing decision.
Finally, word by word, he declared:
"Prepare for battle. All Thousand Sons warriors—ready yourselves. We cannot let Prospero fall without a fight. We will defend it—for our Primarch."
"Also, send a transmission to Terra. We must confirm whether this Exterminatus order truly came from the Emperor's own lips!"
In truth, Amon already believed the Emperor had abandoned the Thousand Sons.
But he was unwilling to surrender without a final struggle.
The younger Astartes refused to die like dogs. They rallied around Amon, ready to defy the invading Primarch legions.
"Amon, this order came directly from the Emperor. What you're doing now… is treason."
Azhek Ahriman spoke up at last.
The surrounding warriors turned to him in shock. None of them wanted to throw their lives away over a letter they couldn't trust.
"Azhek, this is no surprise coming from you," Amon said wearily.
Ahriman was a true Terran. He had once been personally led by the Emperor beneath the Himalayas to receive his gene-seed.
His loyalty to the Emperor was absolute.
"The Emperor has been misled," Amon insisted. "This is a mistake. We must verify the truth."
His argument was logical and well-reasoned. And most of the younger Astartes stood firmly behind him.
"You know how legitimate that letter is," Azhek said coldly. "You've handled enough official decrees to know the procedures inside and out."
"There's no way this order isn't authentic."
"The Emperor does not make mistakes. And no 'traitors' could fool him. If he gave this command, he must have had a reason."
"We must obey. Disarm immediately and submit to judgment!"
Azhek barked out the command with finality.
Seeing he couldn't persuade Azhek, Amon simply gestured for nearby warriors to detain him.
Azhek did not resist. He had expected this.
He accepted the confinement with calm resolve.
He knew he couldn't stop the tragedy that was about to unfold.
With Azhek silenced, the Thousand Sons' senior officers turned to Amon with renewed determination in their eyes.
"Don't worry," Amon said. "We're not entirely without hope."
He had spoken with Jack Wells before and learned that the Universal Megacorp's fleet would not be taking part in the attack.
Their enemies were only the Ultramarines, Space Wolves, Dark Angels, and Death Guard.
There was no winning this fight—only one path remained:
Escape.
The Thousand Sons were the most proficient psyker legion in the entire Imperium.
They had plenty of ways to harass and delay the invading Primarchs.
If they could just escape—then the flame of the Thousand Sons would not be extinguished.
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