The What-If Telephone Booth—this was the version Alexander had rented from the Future Department Store. Its price tag was roughly equivalent to $0.2$ Emperors, or just about one Primarch.
This particular model was highly degraded compared to the version that could fabricate an entirely new timeline from nothing or create a parallel world while completely disregarding causality.
It could not create a timeline out of thin air; it could only manifest a timeline that already held a spark of possibility, allowing a causal parallel world to be born and locating an alternative reality that already existed.
But now, following Alexander's sequence of actions, a specific strand of causality had been torn open. A parallel world that had once been a mere void now possessed the potential to become reality.
The girl glimpsed the What-If Telephone Booth at the final moment. She was struck first by shock—shocked at when Alexander had managed to sell off a Primarch to exchange for this device. Then, realization dawned upon her swiftly. It was Corvus Corax, the Lord of Ravens. The Primarch of the Raven Guard had not been swept away and lost to some Warp storm; Corax had chosen to sacrifice himself, stepping into Alexander's pocket. In a moment when no one was paying attention, he had been traded to purchase this ultimate tool.
But... what exactly was the "what-if" that Alexander wanted to make real?
Was it truly to let Guilliman become the Dark King? No, that would be incredibly difficult. Although the causality of the Emperor becoming the Dark King had been ripped open by Horus's rebellion, it still existed, actively trying to mend itself. Even if Alexander used the telephone booth to manifest the "what-if" of Guilliman becoming the Dark King, it would instantly be crushed and shattered by the dominant causality of the Emperor's ascension...
The girl's eyes widened suddenly as she realized something. He would make that "what-if" a reality, but Alexander's true objective had never been to simply make Guilliman the Dark King. His goal from the very beginning was—
Alexander picked up the receiver of the What-If Telephone Booth. "What if... the world where Guilliman becomes the Dark King becomes real?"
The fan-shaped parallel-space detection antenna atop the booth snapped inward, converging toward the center. A massive electrical surge pierced into the structural fabric of space-time. Dimension itself shuddered as possibilities hidden beneath reality began to rise violently.
Inside the Crystal Gymnasium, Tzeentch's heavily muscled form drifted within the void. The Changer of Ways observed the labyrinthine, intricate web of timelines, desperately seeking even a single path where a Dark King had not been born.
Yet, in every single timeline, a black sun rose. In every single timeline, the causality of the Emperor becoming the Dark King was absolute. The Dark King was being born and rising across every strand of time simultaneously. Even as the Master of Changes—the very symbol of infinite possibility—Tzeentch could no longer forge even a fraction of a new variation, unable to create a single timeline free from the Dark King's shadow.
But at this precise moment, Tzeentch heard a crisp, clear sound, much like a telephone ringing. He looked in astonishment toward the infinite ocean of time. A brand-new, powerful, and distinct timeline materialized out of nowhere in a manner Tzeentch could not fathom, forcibly taking over large swaths of the past. For a time, it actually began to contest the timelines claimed by the black sun.
What... was that?
Tzeentch was utterly bewildered. As he gazed upon those timelines, memories that had never existed before began to surface within his consciousness. Things that had once been non-existent began to seep into his domain. He saw it, he remembered it, he understood it. It was the timeline where the Lord Regent, Roboute Guilliman, became the Dark King.
It was the timeline where Roboute Guilliman, atop the altar of the Macragge's Honour, had slain Horus Lupercal and used the Emperor as a sacrifice to ascend as the Dark King.
As the Master of Changes, there had actually been a brief moment just now where he had forgotten it...
The parallel-space detection antenna on the telephone booth shuddered violently, shifting from red to blue. The crisp ringing of the telephone echoed relentlessly in every corner of this world.
Alexander pushed open the door of the booth and stepped into a world that had already changed from moments before.
The most prominent change was...
Alexander looked toward Roboute Guilliman. The previous silhouette of Roboute Guilliman had completely vanished.
The Guilliman standing upon the snow seemed shrouded entirely in darkness. His once-brilliant ultramarine blue had been dyed a dull, somber shade. The silhouettes of the primordial Four flickered indistinctly behind him, surrendering their power and presence to the Regent. A deep, abyssal light extended from his armor, enveloping his helmet in a cold halo.
The laurel wreath that once symbolized honor and governance upon his brow was gone, replaced by the Chaos Star hanging over his forehead.
In the oldest legends and in the mouths of the most maddened scholars, all seemingly distinct Chaos Gods were nothing more than different facets and avatars of a singular entity. Mad scholars called that presence the Unnameable Sovereign, the One Who Must Not Be Named, the Great Abomination, the Lord of Chaos, the Ineffable Formless Beast.
Yet, that ineffable formless beast was merely a theoretical existence. The Path of Chaos was forever contradictory, forever fracturing, forever spiraling toward madness. Theoretically, that beast could never truly manifest.
But at this moment, a silhouette of that ineffable formless beast seemed to reflect across Guilliman's form. The five corners of the realm of Chaos had submitted in some fashion beneath his intellect, making him powerful enough to rival even the black sun born from the Emperor—the one truly capable of destroying the entire galaxy.
But this power, whether drawn from his regency over the Four or from his erosion of the domain of ruin, carried a strand of illusion. The existence of the black sun and his own existence were mutually exclusive.
Since Guilliman currently occupied only half of the timeline, he naturally commanded only half the power of the primordial Four and directed only half of the erosion and ruin. He could not match a fully realized Dark King, but against that half-dead black sun hanging in mid-air, struggling to be born... they were evenly matched.
The sovereign looked toward Alexander. +I know what you intend to do.+
The will of the Lord Regent intersected with Alexander's. He saw through Alexander's conspiracy, understanding why he had turned a false reality into truth. Yet, he accepted it, simply because...
+I swore to you on the honor of King Konor and Lady Euten. Thus, even if you are playing at conspiracies, I shall uphold my oath.+
+Saint Doraemon, I shall await your competition aboard the Macragge's Honour.+
As his voice fell, the Lord Regent raised his blade high, pointing it toward the black sun. At this moment, both were the Dark King. But there could only ever be one Dark King; their existences were contradictory, and the causal loops forming their beings were mutually exclusive.
The timelines, the Warp, the material universe, the past, the present, and the future were all split into two starkly defined domains. The Lord Regent swung his blade, and a cold sense of order flowed from his steel. The Chaos Star converged to a single point, thrusting toward the black sun. The half-dead black sun shuddered instinctively. Millions upon millions of souls cried out in sorrow within that dark orb—wailing, agonizing, dying, self-destructing, destroying, taking vengeance, bleeding, sacrificing, fading into silence, burning...
Searing solar prominences erupted from the black sun, clashing against the blade wielded by Lord Regent Guilliman. Silence, order, integration, convergence, unification, tranquility, recurrence, all dead, only me...
A force similar to yet distinct from the black sun poured from the blade. Whatever changed did so beneath his will; whatever lived was an extension of his flesh; whatever joy existed sparked from his nerves; whatever blood spilled ran through his veins. All things existed, yet outside of him, all things were nothing. Therefore, the Gods could only exist by relying on him; the Gods could only be ruled through his regency.
The clash between the blade and the prominences completely tore reality apart from the Warp. Causality was fracturing, history was collapsing, and the past was no longer certain. Along with it, the present began to cave in and dissolve. Even the surging tides of the Warp began to fall silent from a loss of structural support. The black sun and the Lord Regent of Chaos battled across every cause, tearing at every effect. Every piece of history was fought over, and every past became a casualty of their mutual destruction. They tore apart every strand of causality the other relied upon to exist—and in doing so, they tore apart the very causality the entire world relied upon to stand.
All things became uncertain. Everything reverted to the gap between existence and non-existence. Only Alexander and the Four Gods managed to barely keep themselves unaffected, continuing to validate their own existences within the Warp.
After a flash shorter than the shortest instant, the causality supporting the births of the black sun and the Lord Regent began to restructure. The altars reappeared. The sacrifices and the priests were manifested from the cracks of time. Those two mutually exclusive sacrifices began to replay themselves in their respective domains...
Horus Lupercal panted heavily, his grip tight around Drach'nyen. He could hardly describe the sensation he had just experienced, almost believing it to be a hallucination. He felt as though he had seen Guilliman shrouded in darkness, looking much like he himself had ten thousand years ago... no, even more powerful than he had been, striking at that black sun until both shattered together. The aftershocks of their fracturing seemed to shatter the entire universe. In that single instant, Horus felt as if every cell, every molecule, and every atom of his being flickered between existence and non-existence. His memories grew hazy and blurred, but the feeling lasted for only a flash. After a brief moment, his form gathered once more, landing upon...
Where was this?
Horus raised his head, looking around in confusion. He was inside a voidcraft, standing within its corridors. The ship gave him a feeling very much like... the Vengeful Spirit?
The Vengeful Spirit of ten thousand years ago, the one that had almost degenerated into a dark altar. The vessel was steeped in a similar atmosphere, yet this was unequivocally not his Vengeful Spirit.
Horus gripped Drach'nyen tightly and looked at his surroundings. He noticed patterns carved into the corridor walls. His sharp gaze caught the star maps of the Five Hundred Worlds and the insignia of the Ultramarines. Could this place be...
"This is the Macragge's Honour."
A voice sounded from behind Horus. He spun around violently. A human of somewhat short stature, with black hair and dark eyes, was stepping toward him. Shadows flickered around the human from time to time, carrying the sounds of insects feeding, stoves cooking food, and the rich aroma of a meal.
Horus sensed a profound threat from this mortal. He raised Drach'nyen...
Wait.
Drach'nyen was resisting. The demon blade refused to let Horus raise it.
+Look, boss, don't point me at this guy.+
+I'm just a sword. Don't go giving me unrealistic expectations.+
"Who are you?" Horus raised the Talon of Horus instead, pointing it forward. Why was the Talon of Horus also refusing to be lifted? The ship's Machine Spirit was actively expressing its discontent.
"I have many names. Many simply call me Saint Doraemon. The Adeptus Mechanicus calls me the Machine God, the Omnissiah, and the Prime Mover. Many people who have eaten their fill, or have yet to do so, call me the Eternal Dragon."
"But my close brothers still prefer to call me Alexander."
Alexander spoke with a smile to Horus. "You may call me that as well, Horus Lupercal."
Now Horus understood why the Talon of Horus and Drach'nyen feared him. Because—"You are the Machine God," Horus said.
Alexander continued to walk toward Horus, but he shook his head slightly. "At this precise moment, I only possess the power of the Eternal Dragon, not the Machine God."
"The Talon of Horus fears me merely because of the lingering residue of the Machine God's aura."
"As for... Drach'nyen, didn't the Golden Jailer teach you anything about acting a bit more proper?" Alexander couldn't help but ask with a laugh.
As they spoke, Alexander came to a stop right in front of Horus.
Horus looked down at Alexander. His lips twitched slightly, and he couldn't help but ask the question clouding his mind: "I have a question."
"You want to know what happened? It's a bit complicated, but I can try to explain it as simply as possible..."
"No." Horus interrupted Alexander, who was about to explain the situation. The Primarch dropped to one knee, though he still looked down slightly at Alexander from his height, and voiced his confusion: "Aren't you a bit too short?"
"How incredibly rude!"
Aboard the Vengeful Spirit, Alexander—surrounded by Mini-Doraemons, with the occasional sound of turning gears and venting steam echoing around him—voiced his complaint.
Sanguinius couldn't help but let out a small smile. Looking at Alexander, who was visibly much shorter, he said, "Your current height, even for a mortal, qualifies as exceptionally short."
"Allow me to say something even ruder: you are already within the blast radius of a dwarf joke."
"So what? If it hadn't been Guilliman or the Emperor becoming the Dark King, but Jaghatai Khan instead, I might have survived simply because I'm shorter than a bike wheel," Alexander countered with a laugh.
"You missed a detail. This should be the 30k era. Right now, the White Scars are equipped with jetbikes. There are no wheels."
"Ah, so that's why the Leagues of Votann didn't dare show their faces during 30k. It turns out having no wheels at all is even harsher than flattening them."
Alexander spoke with a chuckle, his gaze sweeping down the deep corridors of both the Vengeful Spirit and the Macragge's Honour...