Part I - The Princess's Projects
Aurelia walked with deliberate grace through the secret passages that laced the lower levels of the Golden Tower, a labyrinthine journey she had made her routine since her awakening. These hidden routes, sealed against all but the highest clearances, were extensions of her will, silent guardians of forgotten lore. Eight Adeptus Custodes, silent giants in burnished auramite, followed her, their footfalls hushed, their obedience absolute. Yet, at her side strode a figure of far stranger aspect: Belisarius Cawl. He moved with a series of mechanical clicks and whirs, a symphony of augmetic prosthetics and whirring sensors. A very old friend, one she had never truly expected to see again in the flesh, yet here he was, a living relic of her past, his multi-limbed form almost vibrating with barely suppressed excitement.
Their friendship, forged during the tumultuous end of the Great Crusade and tested by the horrors of the Heresy, was a unique bond. Cawl was not the sole Tech-Priest she had cultivated alliances with, but he was undeniably the last of her close confidantes from that era. His eccentricities had deepened with millennia of cybernetic augmentation and self-experimentation, his intellect sharpened to a razor's edge. In some ways, he was more mad, in others, profoundly wiser. But for Aurelia, he remained the same relentlessly curious mind, always eager to push the boundaries of technology, the most prolific and undeniably pivotal Archmagos Dominus of the Adeptus Mechanicus in this grim age. Together, they made their way towards Aurelia's vast, subterranean laboratories, a hallowed space brimming with her deepest, most guarded wonders.
"I have heard of your great project, my friend—the Primaris Space Marines," Aurelia began, her voice gentle, yet imbued with an underlying strength. "My brother, Roboute, recently journeyed to Mars to witness them personally. He spoke of their numbers. How many have you now brought forth?"
Cawl's binary breathing filled the large, echoing halls of the Golden Tower's underground network, a staccato rhythm of cogitation. "Over one hundred thousand, if my memory banks serve me precisely, Your Highness. Perhaps more by the latest calculations." His servo-skull whirred, dutifully projecting a tally that scrolled across the ancient stone. "A greater multitude shall follow in the coming years. My automaton legions are kept in continuous overdrive, even as the first batches are now deployed across the stars."
Aurelia hummed, a low, contemplative sound. One hundred thousand. It was a number she had not heard in relation to Space Marines since the Great Crusade itself. Could such a force truly turn the tide? She harboured no illusions; it would be a powerful boon, an undeniable reinforcement, but the insidious corruption of ten millennia ran deep. True change would demand more than soldiers. That was why she was here, and why she had summoned Belisarius Cawl to Terra.
"My sincerest apologies, my friend," Aurelia said, her gaze sympathetic. "I find myself anchored to Terra. I cannot, as I wish, visit Mars and witness your magnificent work firsthand."
"No apologies are required, Your Highness," Belisarius replied, his voice unexpectedly gentle, stripped of its usual binary inflexions. He spoke as if to an old, cherished companion, perhaps the only being in the galaxy he held in higher esteem than the Omnissiah itself. He was, undeniably, also immensely pleased to be counted among the vanishingly few, perhaps the sole Archmagos, to be permitted entry into Aurelia's most secret forge.
"I know," Aurelia responded, a soft smile playing on her lips. "Yet, my friend, we require more than mere soldiers. Did the mineral I entrusted to you… Did it meet with your exacting standards?"
Cawl whirred with barely contained excitement, his optical sensors gleaming. He nodded emphatically, his servo-skull projecting a rapid-fire cascade of data. The mineral, a creation of the Princess herself, was not merely a superior alternative to adamantium, ceramite, and even the sacred auramite; it possessed intrinsic regenerative properties akin to a refined Necrodermis. Noverrium, a living metal that promised to fundamentally alter the course of war, was nothing short of miraculous.
Cawl had already incorporated Noverrium into certain key components of Guilliman's Armour of Fate, and the preliminary trials had exceeded even his most ambitious projections. He knew, with absolute certainty, that if this living metal could be woven into every new Mark X Power Armour, the enemies of Mankind would be profoundly shocked by its capabilities. Even the ancient Necrons, the very masters of living metal, would be stunned by humanity's audacious claim to their singular technology. And Cawl, ever the showman, relished the prospect of rubbing this triumph in their silent, cold faces.
"It is a truly marvellous mineral, Your Highness. Noverrium. Intuitively understood by machine-spirits, pliable to manipulation, robust beyond measure. Its properties are… exceptional. The quantity, however, remains insufficient for the demands of the nascent Primaris Space Marine legions."
Aurelia sighed, a soft sound of gentle understanding, and nodded. "I am aware. I had barely enough to conduct initial trials on my brother's panoply, and on other critical components. However, you need not trouble yourself with scarcity. I shall replenish your vaults with Noverrium, and they shall never again know emptiness."
Belisarius Cawl's optical sensors widened as they approached a colossal blast door, ancient and unadorned, save for a small numeric keypad and an archaic cogitator terminal. Aurelia hummed softly, her eyes glinting with amusement as she stepped towards it.
"No peeking, old friend," Aurelia cautioned, her voice light, and Belisarius Cawl permitted himself a series of discreet binary chuckles that amounted to an amused snort.
"Pass‑phrase," the Cogitator intoned.
The Princess's slender fingers danced across the keypad, typing the first password with practised ease: "ABSOLUTELY_NOT_ALPHARIUS".
A small, green light flickered. She typed the second, a fleeting smile playing on her lips, her eyes twinkling with mischievous humour: "FORTIFY_THE_LEMONS".
She could almost hear Rogal Dorn's long-suffering sigh in the depths of her mind.
A third password followed: "MALCADOR_STOLE_MY_TEA". And she could hear, almost, her uncle Malcador walking away laughing with her tea.
The door hummed, a deep, mechanical groan reverberating through the passage as ancient seals began to flex, its machinery awakening. Belisarius Cawl, ever reverent, offered a silent, binary prayer for the machine-spirit.
Finally, Aurelia returned to the keypad, tapping the last, deceptively simple code: "0123456789."
The last digits were entered with a deliberate flourish of childlike glee that no one, save her Custodes, were permitted to witness.
With a final, profound sigh, the immense door parted, revealing Aurelia's clandestine laboratory. It was a staggering shift from the pristine, gold-and-white elegance of the Golden Tower. This was a realm of profound darkness, illuminated by the cold, precise glow of arcane machinery crafted by her own hands. Tools and devices, born of knowledge gleaned from the forgotten depths of the Dark Age of Technology, melded seamlessly with the alien insights she had gleaned from the C'tan, Old Ones and Necrons. It was a workshop where time and convention held no sway.
Belisarius Cawl's many optical sensors flared, whirring in stunned, incredulous pleasure. "By the Omnissiah's sacred wisdom… what a truly magnificent place, Your Highness!"
"Thank you," Aurelia replied, her voice soft with satisfaction as she stepped into the immense space she had personally crafted. "I have laboured here for months, designing new schematics and refining other long-held projects. One pressing matter is the accelerated rebuilding of the Adeptus Custodes' numbers. The original process is painstakingly long, friend. I have a method to make it swifter."
"Oh? Does the Emperor… approve of this acceleration?" Cawl inquired, genuinely intrigued, a thousand new thought processes sparking in his multi-segmented brain.
"He taught me the very principles of their creation. And, like any inventor, one always finds ways to enhance, to refine, to improve the process," Aurelia replied, guiding him towards a colossal cogitator array, its vast displays flickering with complex data. "We need numbers, Belisarius, and time is a cruel tyrant. If I can accelerate their creation, then the principles can be adapted for your Primaris."
Belisarius Cawl's servo-skull emitted a series of rapid binary questions, querying the sheer impossibility of such acceleration.
"Humanity, my friend, of ancient times, had a saying: Necessity is the mother of all inventions." Aurelia's voice resonated with profound, ancient wisdom. "Humanity, even in this grim age, has not forgotten that." She gestured towards another vast chamber.
Her fingers moved across the console, and a section of the wall slid away, revealing a circular chamber beyond. It was a library of impossible scale. Towering pillars, hundreds of feet high, were filled with perfectly arranged data-slates. But it was the object at the chamber's centre that drew Cawl's entire being. It was a giant, slowly rotating sphere of pure, blue light, humming with unimaginable power. Data-slates were materialising from its surface every second, collected by swarms of servo-skulls and slotted into their places on the pillars. Cawl knew what he was looking at. He was looking at the heart of the Mechanicus faith, a thing of myth and legend. A true, complete, and enormous Standard Template Constructor core. Or something more than just that. A machine of its own.
"My Princess, this is… this is by the Omnissiah… beyond wonderful!" Cawl whispered, his voice hushed in genuine awe. He gazed upward, columns of information vanishing into the gloom, a dizzying vertical cityscape of technology and weaponry beyond his wildest dreams. The sheer volume of hidden knowledge, of untold marvels stored within this vault, defied all comprehension.
Aurelia smiled, stepping closer to the massive, spherical core. "That colossal sphere… that is my own creation. My version of the Standard Template Constructor. I call it EVA. It is not an Abominable Intelligence, Cawl. Not in the way the Mechanicus understands it. Consider it an exceedingly advanced cogitator matrix, linked intrinsically to my own memory. Or so I will say. I completed it at the conclusion of the Heresy, but had not, until these last few months, had the time to fully bring it online."
"What… what does it do?" Cawl asked, his usual binary self-control momentarily abandoned.
"You, my friend, are likely the only individual in the galaxy who could comprehend this," Aurelia whispered, her celestial eyes locking onto his. "But I trust you, Belisarius. And… this is the correct path." She deliberately closed a mental chapter, her focus settling solely on EVA, her almost-not-AI. "It draws directly from my mind. I have seen the Dark Age of Technology—the whole book, not a page. I know the path to the Age of Strife. But I am not here to offer you a history lesson. Instead, EVA synthesises all available information—everything I have seen, everything I know—and manifests fragments of lost technology onto these data-slates, for our use."
Aurelia took a single, polished data-slate from a dispensing slot. A holographic image bloomed above it: a magnificent military tank, so advanced it made Cawl's internal augmetics whir in sheer delight. Aurelia did not need to state that EVA was also processing knowledge gleaned from the Old Ones, the C'tan, and the Necrons, integrating it into truly novel, hybrid technologies.
"This, my friend, is the true library that will lead humanity into a new age. I have meticulously purged any trace of Abominable Intelligence; only beneficial, uncorrupted knowledge remains. But as you can discern," Aurelia swept her hand towards the towering pillars of data-slates, "we shall want for nothing more. Everything we would ever want is here, and if we need more, we just need EVA to give it to us."
"Your Highness! This… this could elevate humanity, the Imperium, and Mars into a new Golden Age of Technology!" Belisarius Cawl's excitement was a roaring, binary crescendo. "The paradigm shift this could generate is… incomprehensible!"
"Easy, my friend. Do not attempt to bite off more than you can chew," Aurelia replied, a gentle smile returning to her lips. "Such a height will demand centuries for humanity to truly reach, and remember, time is not a luxury we possess. Our immediate focus must be the capacity to wage war against enemies who are stronger than we are. For humanity to attain such a new age, first, we must secure victory in this Crusade."
Belisarius Cawl, chastened yet still buzzing with a profound, almost religious zeal, composed himself, his many optical sensors devouring the technology being manifested around him. "I comprehend, Your Highness. My apologies. My excitement momentarily rendered me… youthful again."
"No need for apologies. Here." Aurelia handed Cawl a small stack of data-slates. "These should significantly accelerate the deployment of Primaris Space Marines."
Belisarius Cawl took the data-slates, his mind immediately beginning to parse their contents. One particular schematic depicted a pod unmistakably, a variation of the very Edenic stasis pod that had cradled Aurelia. Yet, this version was designed not merely for preservation and healing, but for exponential growth acceleration. Cawl's genius immediately connected the dots.
"Brilliant!" Cawl simply stated, his voice a profound, almost reverent whisper. He understood. This pod, and the accompanying schematics for genetic recalibration, would allow him to accelerate the process of genetic implantation and surgical modification of mortal aspirants into Astartes, drastically reducing the time required for their transformation and healing. Other data-slates outlined rapid organ growth, advanced bone-knitting, and even refined Rubicon Primaris procedures, further solidifying the super-soldiers' resilience. But Aurelia's voice cut through his torrent of data.
"Brilliance is not enough, my friend," she said, her tone becoming serious. "I need loyalty. I need minds that will not shatter when faced with the new. This knowledge cannot fall into the hands of dogmatists or the shortsighted. Give me names, Belisarius. Tech-priests, Forge Worlds... who among your kind can be trusted to build the future, and not just worship the past?"
Cawl's optical lenses focused on her, the whirring of his internal mechanisms a thoughtful hum. "The list is shorter than it once was, but stronger for it," he replied after a moment. "There are those who have long chafed under the yoke of stagnation. Ryza, with its expertise in plasma weaponry, will be eager for new fire. Metalica's martial pride will see the logic of superior arms, even if they don't tolerate me much." He paused, a series of clicks echoing in his vocalizer. "And I have... apprentices. Minds I have personally cultivated over the centuries, who understand that the Omnissiah's truest blessing is not rote catechism, but endless innovation. They will answer the call, Your Highness. They have been waiting for it for a long, long time."
Aurelia nodded as she looked at the chamber.
"I will permit you to take a few dozen more data-slates, my friend. Whatever you need to make the Primaris Space Marines stronger, and the Astra Militarum more resiliant. I have already begun transmitting preliminary schematics to the Laurel Systems; they are to become the industrial heart of the Crusade. But I will require Mars to maintain, indeed, to exceed pace." Aurelia replied, her voice firm. Belisarius Cawl emitted a low, satisfied hum, his excitement barely contained.
"Mars shall be most content with this bounty," Cawl promised, already envisioning a thousand new forge-temples roaring to life.
"And now, for Noverrium," Aurelia said, leading him to yet another immense machine, its form vaguely reminiscent of an STC sphere, yet wholly unique. Here, instead of data-slates, colossal blocks of shimmering, opalescent Noverrium were being continuously extruded. Cawl let out a delighted, guttural cackle, his optical sensors fixated on the endless, flowing stream of living metal. He looked back at the Princess, a wild grin spread across his metallic face.
"How much, Your Highness, should I… appropriate?" he asked, though he already knew the answer.
"As much as you require, my friend," Aurelia replied, a smile playing on her lips, her eyes filled with the endless promise of her own inexhaustible will.
Part II - A Fleeting Peace
There were moments, Aurelia knew, that were more precious than any jewel forged in the heart of a dying star. This was one of them. The Indomitus Crusade loomed, a galaxy-spanning storm that would soon pull her brother into its vortex, and it might be years—or centuries—before they shared the same quiet air again. So she gave him the only gift she could: a sliver of peace, an island of stillness in an ocean of impending war.
Within the silent grandeur of her chambers in the Golden Tower, Roboute Guilliman lay with his head resting on her lap. The great sofa, upholstered in velvet, the colour of a midnight sky, seemed to shrink around them. Light from the ever-lamps, muted to a soft, golden dusk, caught the threads of silver in his blond hair. His eyes were closed, the harsh, pragmatic lines of command and ten millennia of grief softened by the gentle hand of sleep. His breathing, usually so measured and controlled, was deep and even, the slow, rhythmic rise and fall of his chest a quiet testament to his exhaustion. For the first time since his return, he looked not like a demigod burdened by the fate of a trillion souls, but simply like a brother, at rest.
Aurelia's fingers gently traced the lines on his brow, a gesture as ancient as their shared childhood. She felt the knot of tension there, a ceaseless hum of calculation that even slumber could not fully erase. A soft, ancient lullaby hummed from her lips, a melody from a time before the Imperium had a name, a song she had once sung for all of them. The memory rose, unbidden and bittersweet: a similar afternoon on a world long lost, with Horus, his laughter echoing as she braided a garland of flowers for his amour; another, with Magnus, his single eye closed in thought as she read to him from a forbidden text. A wave of profound, aching love washed over her. She loved them all, every last one, from the brightest to the most damned. It was a truth that would be called the blackest heresy in this dark new age, but it was her truth. No one else had known them as she had. Not as generals, not as legends, but as boys, as men, as family.
She could not share their burden on the battlefield, could not lift the impossible weight of their command. But she could offer this. A sanctuary. A moment to be vulnerable, to be human, to simply be. She felt the ceaseless tornado of his mind, the endless calculations, the logistical chains, the crushing weight of a million million lives entrusted to his care. But for now, that storm was quiet, held at bay by the simple, profound act of a sister's love. She wished she could grant him a thousand years of such peace. Four hours would have to suffice.
Aurelia leaned down, her cosmic hair forming a celestial veil around them, the faint light of nascent galaxies shimmering in the gloom. She pressed a gentle kiss to his forehead. "Brother," she whispered, her voice soft as starlight. "It is time."
Guilliman's eyes fluttered open. For a single, unguarded second, the brilliant, strategic blue was unfocused, the gaze of a man pulled from a dream he could not quite recall. Then clarity, and the immense weight of duty, crashed back in. He stirred, a giant waking, and the illusion of peace shattered.
"How long?" he murmured, the word rough with sleep.
"Four hours," she answered, a tender smile playing on her lips.
He sighed, a deep, resonant sound that seemed to carry the weariness of ages, and sat up, rubbing his temples as if to ward off an oncoming headache. "I told you one."
"And I chose to be a disobedient little sister," she replied, her smile widening into a gentle smirk. "You needed the rest. The fate of the galaxy can wait for you to be properly awake to bear it."
He did not argue. He knew she was right. For a long moment, they sat in a comfortable, shared silence, the kind that needs no words to fill it. Aurelia leaned against his broad, armoured shoulder, feeling the solid, reassuring presence of him, a mountain of strength and stability in a crumbling galaxy.
"The Crusade begins at dawn," Aurelia whispered, her voice barely disturbing the stillness. The question hung unspoken in the air between them. "How do you feel?"
Guilliman took a deep, measured breath. He could not lie to her; he suspected no one could. In her presence, the carefully constructed facade of the unflappable Lord Commander could be set aside. "It feels… larger than me," he admitted, his gaze distant, fixed on a point beyond the chamber walls, on the wounded sky of Terra itself. "Larger than any war I have ever fought. I look at the maps, at the Cicatrix Maledictum tearing reality asunder, and I feel… inadequate. A single man attempting to dam an ocean of ruin. I stand before it and feel unequal to the task."
Aurelia took his hand, her slender fingers lacing through his larger ones. A wave of calm, of quiet strength, flowed from her, an aura of absolute belief that was more potent than any psychic ward. "You will face challenges that seem insurmountable," she said softly, her voice unwavering. "You will suffer defeats that will wound you to the core, and you will see horrors that will test the very limits of your soul. But you will learn, you will adapt, and you will lead this crusade to victory. You will not fail."
He looked at her then, his blue eyes searching hers, a flicker of desperate hope warring with a millennium of ingrained pragmatism. "Did you see this? In one of your… chapters?"
To his surprise, she shook her head, her star-strewn hair swirling like a captured nebula. "No," Aurelia replied, her voice soft but firm. "I choose not to witness every thread of fate. I only permit myself a single chapter when the direst situation demands it or when it is important to know the next step, lest I become the very thing I despise. To comprehend every permutation, to play with the lives of billions like pieces on a board… I would become humanity's Tzeentch, a tyrant of destiny, deluding myself, I am doing it for the greater good. So, I choose only hope and belief. I believe in you, brother. I hope the crusade will find triumph."
"Hope," he whispered, the word feeling foreign on his tongue, a concept he had long ago archived as a strategic liability.
"Yes. Hope," she affirmed. "It is the most human of all things, the engine of all great endeavours. Let us hope, and let us believe in what we can accomplish."
A rare, genuine chuckle escaped Guilliman's lips, a sound that seemed to chase the shadows from the room. "What about the times you used your 'chapters' to play pranks on us? I distinctly recall you always knowing where I had hidden my quills, only to find them relocated to the Lion's personal study, much to his grim confusion."
A faint blush touched Aurelia's cheeks. "That was harmless fun," she mumbled. "And he deserved it for being so dour. It was a tactical redistribution of assets to improve morale."
The moment of levity passed as quickly as it had come, and the weight of the present returned, settling upon them like a shroud. "It is time for me to go, sister," Guilliman said, his voice once again that of the Lord Commander. The change was subtle but absolute.
"I know," she sighed, the sound heavy with unspoken farewells.
"And I trust you understand that my orders regarding your protection are not negotiable."
Aurelia's expression shifted to one of mild exasperation. "Brother, you cannot be serious. There is no need for you to create me an entire Space Marine Chapter. I have the Adeptus Custodes and the Anathema Psykana. My guards are the finest warriors in the galaxy. And I rarely, if ever, depart the Golden Tower."
Guilliman's face became stern, the indulgent older brother replaced by the unyielding Primarch whose memories were etched with the fires of betrayal. "The Custodes' numbers are dangerously depleted, and many of their finest will be joining the Crusade fleets. Even with your accelerated creation process, it will take time to replenish their ranks to full strength. I lived through one galactic civil war, sister. I saw brothers turn on brothers. I will not leave you unguarded. Captain-General Valoris agrees with my assessment."
"I am not unguarded," she muttered, pouting in a manner so childlike it was almost comical on a being of her age and power. She crossed her arms, a silent, petulant protest.
"I will leave a Victrix detachment in rotating strength. With a small force of Ultramarines, that would serve you. As well, for you to get used to having your own chapter."
"I assume this is a direct order from the Lord Commander and First Consul?" she grumbled, her voice laced with mock formality. Guilliman's lips twitched, fighting a smile at the familiar sight.
"It is," he confirmed, rising to his full, towering height, the air around him seeming to solidify with his authority. "And you will be a good little sister and obey your older brother on this."
She sighed in theatrical defeat, though a small smile betrayed her amusement. "Very well. You win this battle."
"Of course," Guilliman said, the corner of his mouth ticking upwards in a rare, almost boyish smirk. A hint of smug satisfaction coloured his expression.
"Victory, sister," he added, his voice a low, rumbling counterpoint to her sigh, "is, after all, what I do best."