Adam's pen hovered gently above the Book of Ages.
He paused to reflect.
Altering history required finesse. Adam made a quick mental calculation. While the T'au lacked any major underlying backing, they had crossed paths with several significant powers throughout their six-thousand-year evolution.
For instance, upon stepping into the void, they immediately ran into the Orks—a cosmic plague spreading unchecked across the galaxy—engaging in long, bloody conflicts with the greenskins. On other occasions, they had direct skirmishes with the Imperium of Man. Furthermore, though the Ruinous Powers behind the Veil cared far less for this minor race than they did for humanity, their eyes had drifted toward this planet more than once.
Consequently, he could not rewrite this six-thousand-year progression wholesale. Doing so would drastically intensify the universe's temporal rejection, snapping him back to the correct timeline in the very next second—or worse, drawing the immediate attention of the Chaos Gods.
That would be disastrous. Adam intended to reserve his ultimate trump card for the endgame; he could not afford to expose his hand prematurely.
So, how to proceed?
After a moment's thought, an idea struck him.
Got it.
The Fall of Caliban!
That was a classic case of effect preceding cause. To stop the Fallen from traveling back in time, the Dark Angels Chapter Master ignored the gentle warnings of the Tuchulcha Engine, accidentally blowing up historical Caliban in the process and creating the Fallen in the first place. In a way, it was an quintessentially Warhammer twist—a trope documented across all manner of time-travel fiction.
With that blueprint in mind, Adam formed a clear strategy. As long as the rise of the T'au remained intact, he only needed to tamper with the underlying cause behind that rise.
It was simple enough.
With his plan set, Adam set pen to paper with divine fluency, the quill scratching rapidly across the pages of the Book of Ages.
As he wrote, the clouds above primitive T'au Prime parted abruptly.
A pitch-black vessel—crafted by Adam's reality-warping to appear as a Dark Age of Technology human ship—emerged from the warp rift, descending slowly through the cloud layer. Streamlined and completely devoid of markings, its thrusters trailed long arcs of flame across the twilight sky.
The primitive T'au looked up from their settlements, mouths agape in utter astonishment. They had never seen such a construct; in their minds, the sky belonged solely to birds and clouds. This black behemoth clearly belonged to neither.
At this era, the T'au were already divided into basic tribes.
Those dwelling high in the mountain ranges, relying on skills passed down through generations, crafted hot-air balloons and gliders to navigate the high altitudes. They were the predecessors of the Air Caste, adept at riding air currents between cloud and peak.
The tribes inhabiting the dense jungles were skilled craftspeople who devised and constructed various tools. They were the predecessors of the Earth Caste, turning wood and stone into weapons and containers.
The desert tribes were fierce and warlike, their warriors tempering a ironclad will from childhood through battles with wild beasts. They were the predecessors of the Fire Caste.
And then there were the specialized tribes that mediated disputes between the others—eloquent speakers who knew how to find balance among conflicting parties. They were the predecessors of the Water Caste.
Yet in this moment, Earth, Fire, Air, and Water Caste ancestors alike stared blankly as the black ship slammed heavily into the earth.
A deafening crash shook the ground. Dust and debris erupted skyward like fountains, the shockwave flattening the flimsy fences around their settlements. Fires spread outward from the impact crater before being smothered beneath the settling earth.
The primitive T me gathered around the crater from a safe distance, none daring to draw near.
Days passed before the fires around the crash site finally died out completely. The dust settled.
Eventually, a curious and hesitant T'au took a step forward. Barefoot on the warm gravel, he walked step by step toward the black ship. Behind him, the entire tribe watched in silence.
The T'au disappeared inside the ship. A day later, he emerged.
Every gaze locked onto him. His appearance had undergone a radical transformation.
Where the flat, featureless T'au face once was, his features were now sharp and defined. His skin retained a blue-grey undertone, yet possessed an unfamiliar, subtle sheen. Most striking of all, a raised nose sat prominently in the center of his face—an organ no T'au had ever possessed.
Dark hair cascaded from his scalp down to his ears, and his limbs had become proportioned, long, and athletic, ending in fully formed five-fingered hands.
The man smiled.
The bewildered T'au were utterly baffled. Yet the transformed individual simply smiled and rejoined his kin. He sat by the campfire, ate, and conversed as though nothing had changed.
Yet the true transformation had only just begun.
In the days that followed, under the watchful eyes of his peers, the individual who had entered the black vessel displayed unprecedented capabilities.
His body was sturdier than the strongest Fire Caste warrior; in tribal disputes, he could easily throw the fiercest fighter to the ground unarmed. His mind was sharper than the wisest Earth Caste artisan, fashioning repeating crossbows from a few branches and hides. His mastery of air currents and airborne maneuvers left the most experienced Air Caste pilots stunned. His logic was so compelling that even the most stubborn Water Caste mediators found themselves nodding in agreement.
He embodied the apex traits of every caste combined.
The man earned an ever-growing legion of followers across the settlements. When the T'au pressed him for his secret, he pointed to the black ship.
Driven by a desire for strength, the demands of survival, and sheer utility, the T'au—who had yet to form a unified identity—entered the vessel one by one. And like the first, they emerged tall, athletic, and transformed overnight into a practically new species.
With their newly augmented bodies, these T'au began advancing their civilization at a staggering pace.
Adam floated in midair, watching the scene unfold with a calm smile. He raised a hand and flicked his wrist. Under his direction, the T'au began organizing into specialized roles based on individual talent. The caste boundaries remained, but they were no longer absolute rigid mandates.
A Fire Caste warrior remained a warrior, and an Earth Caste artisan an artisan; yet if a child raised among the Fire Caste showed a natural knack for crafting, they were free to join the Earth Caste. Castes shifted from a rigid, biologically mandated caste system into a natural selection based on personal aptitude and choice.
Through total cooperation, their civilization leaped forward at unimaginable speed. They mastered metallurgy, civil engineering, written language, and mathematics.
Naturally, the integration was not without bloodshed. From primitive stone-tool users, they rapidly escalated to black powder and steel. Wars erupted between settlements over territory and resources: Earth Caste gunpowder shattered fortress walls, Fire Caste warriors charged on tamed beasts, and Air Caste aeronauts dropped incendiary vessels from above.
War. Slaughter. Conquest.
Then, at the height of the chaos, another group stepped out from the black ship.
Calling themselves the Ethereals, their voices carried a soothing authority capable of calming the fiercest Fire Caste warrior in seconds. As time passed, these Ethereals walked into the central squares of every settlement to speak. Their words fell like rain on parched land, prompting warriors to lower their weapons and listen.
At incredible speed, they bound all T'au together into a unified whole.
A great empire was born.
Adam closed the Book of Ages. Nodding in satisfaction, he slipped the heavy volume back into the void and brushed off non-existent dust from his hands.
His task was complete.
He turned to leave, but paused at the edge of the system's orbit to look back one last time.
Reaching out into the warp surrounding the planet, Adam stirred up a warp storm identical to the one in the original history. It was a storm that had always existed in the timeline; he simply ensured it erupted at this exact moment.
When the Imperial fleet—responding to the distress signal from the Land's Vision—arrived, they were met only with tempestuous warp tides engulfing the system. Shaking their heads, they turned back.
Another fleet attempted to bypass the storm, surging full-throttle toward the planet. The hulls of those ships bore faint, intricate patterns—identical to the markings Adam had seen on Elder Aun'Va's robes. Clearly, these were unfortunate interlopers from the original timeline attempting to reclaim what was lost.
Heh, you're the real intruders here.
Adam cast a casual glance in their direction. Moments later, those ships dissolved into nothingness in the cold void.
With everything settled, Adam snapped his fingers.
The chaotic flow of time roared around him. Images of the past flashed in reverse like pages whipped by a hurricane.
Then, Adam opened his eyes.
893.M41.
He had returned to the correct timeline.
Floating once more above T'au Prime, Adam looked through the clouds at the thriving world below. Barely any time had passed in the present, yet everything had changed.
Recalling what he had set in motion, a satisfied, expectant smile spread across his face.
Now, it was time to witness the results.