Author's Note: Well, I like Code Geass, and I like Warhammer 40k. A friend of mine suggested to me to combine these two awesome things, and so this story was born. Taking place about ten thousand years after the current Warhammer 40k canon (hence the title), I've borrowed a few elements from the Black Library format, most notably the opening paragraphs. Anways, sit back and enjoy! While this may not have Warhammer's distinctive GRIMDARK elements at first, rest assured, it's coming.

Disclaimer: Agh. I'm too used to writing for sites where the disclaimer is understood. Anyways, I do not own Code Geass or Warhammer 40k. If I did, there would be agreement as to how Is(s)tva(a)n is spelled! And the arrival of the Lancelot would not derail Lelouch's plans every time!

Prologue: Tears of the Emperor

Lelouch Lamperogue awoke to the sound of knocking at the door, the sound audible even through the adamantium. He groaned, sandwiching his head between pillows in a futile effort to drown out the sound. The knocking only grew louder and more persistent. When it stopped after what seemed like an eternity, Lelouch breathed a sigh of relief, hoping to get a few more minutes of sleep before being confronted by the mountain of paperwork that doubtlessly awaited him. He was beginning to think that Malcador's vaunted Administratum was more trouble than it was worth: whatever paperwork it saved him was made up for by the bureaucracy that kept the organization running.

His eyes shot open when he heard the bedroom door opening. The list of people who could freely enter his bedroom was very, very short. Most of the select few never came across matters so important that they couldn't wait until his work day officially began. The others were scattered across the galaxy, taking some well-deserved time off. The last five hundred years had been a long, hard slog for them all of them, uniting the scattered worlds of humanity under the banner of the Imperium. The Great Crusade was over, and they all needed some rest before the task of consolidating and maintaining their gains began.

"If it's the Eldar throwing another tantrum over the treaty, I don't want to hear it. I've been more than generous with them, and my patience is at an end," Lelouch grumbled as he draped a robe over himself. He got out of bed carefully, as to not disturb CC, who still slept peacefully. She moaned slightly as a source of warmth suddenly left her side, but she didn't wake.

"Father, perhaps Fulgrim and I should have a talk with them?"

The booming voice jolted Lelouch fully out of his half-asleep state, as a wall of pale green suddenly appeared in front of him. He looked up, seeing the grinning face of Horus, who, despite being created in a genetic lab, was the closest to a son that he had ever had. The much larger man laughed and swept Lelouch into a hug that would have crushed the bones of any normal man. Lelouch could swear that he heard a few of his bones creaking under the pressure, despite having withstood much, much worse during the Crusade.

"Back from your vacation already?"

CC opened her eyes, stretching lazily before pulling on a robe and padding over to the other two. While her golden eyes remained passive, the corners of her mouth tilted upwards slightly in a rare half-smile. Though she didn't play favorites amongst the Primarchs, at least not as blatantly as Lelouch did, she would admit that she liked Horus much more than some of his other brothers, especially Alpharius, who always seemed to be up to something.

"Yes, mother," Horus turned back to Lelouch, "I stopped by Laeran on the way back. Fulgrim sends his regards, as well as somebody you would probably like to s-"

"Onii-chan!"

At speeds impressive even to a Primarch of the Astartes, a young brunette psychically flung herself at Lelouch, practically knocking him over. When Lelouch sufficiently recovered from the sudden impact and forced air back into his lungs, he returned the hug.

"Nunnally! How was your tour of the Imperium? I trust the Primarchs treated you well?"

Horus watched as the person that the Primarchs unanimously agreed was their favorite "aunt" launched into a high-speed tale of the last few years. Lelouch had made abundant promises to his younger sister that, when the worst of the Great Crusade was over, he would accompany her on a trip around the Imperium. Several years earlier, with all but the Eastern Fringe pacified and the Great Crusade in the last stages of winding down, he finally made good on that promise. The Primarchs had scrambled to be the first to host their favorite aunt, though Lorgar had won in the end, outmaneuvering even Alpharius.

As Nunnally described the rolling plains of Prandium, a world that Guilliman had proudly shown her when it was his turn to play host, she suddenly froze. Her expression became slack, and her eyes glazed over. Her jaw hung open in mid-sentence. Lelouch waved a hand in front of her face, shaking her slightly as his panic became evident. Nunnally wasn't the only one, as CC and Horus were in a similar condition. Fear, an emotion he had rarely felt even during the worst of the Great Crusade, began to seep into his mind.

As he was near the verge of panic, a blinding flash of light appeared before him. He could see a figure silhouetted in the light, but couldn't make out any features. It seemed to be female, and carried a staff by its side. Before he could demand an explanation, the figure spoke.

"Lelouch, this is all an illusion crafted by your enemies to weaken you. You must see past it!"

The voice was definitely female, and was soothing to him. The panic slowly melted away, replaced only by calm. Before he could ask anything, the figure turned around, and vanished into the light.

As if nothing had happened, Nunnally animatedly continued her tale. She trailed off when she noticed Lelouch freeze.

"Onii-chan?" she asked, concern evident in her voice. When she reached to grasp his hand, he jerked back as if burned. She froze as she noticed the sword in Lelouch's hand, alight with psychic fire.

"Onii-chan?" she asked again, this time with fear in her voice.

"None of this is real. It's all an illusion," Lelouch repeated to himself constantly, as he approached the cowering form of Nunnally. Squeezing his eyes shut, he swung his sword down. Then he leapt towards where he knew the CC-lookalike was standing, then towards where the Horus-lookalike was. There were several screams, and, when he opened his eyes again, the happy illusion was shattered. In front of him lay not the broken bodies of Nunnally, CC, and Horus, but the corpses of foul daemons. Surrounding him was not his bedroom, but the maddening dimensions of the Immaterium.

"Fool! You should have just stayed in the happy illusion I constructed for you!"

The booming laughter brought for a legion of daemons, which Lelouch could clearly see carried the mark of Tzeentch. He wasn't awfully surprised. Raising his sword aloft, he charged into the horde, hacking and slashing in every direction. Even with only slivers of his power available, even the hordes of daemons were no match for him. As soon as he dispatched the last one, the voice spoke again, as the Warp melted away.

He found himself standing amidst the wreckage of a city now, the broken bodies of countless hundreds of Japanese lying around him. He knew this scene well, as it was Tzeentch's favorite way of tormenting him. He could feel his arm rise on its own volition, even as he screamed for himself to stop, raising the gun level with the chest of the pink-haired girl barely two meters from him. He could only watch as he squeezed the trigger, watch as the pink-haired girl fell to the ground in an almost-graceful arc. There was a brief flash, and he was holding the gun once again, raising it to chest of the girl in front of him.

Over a bulk of what was once the Euro Universe of Old Terra now stood the monumental Imperial Palace, a series of enormous pyramids reaching kilometers into the sky. Deep in the heart of the largest of these pyramids laid the Sanctum Imperialis, the single most heavily-guarded room in the Imperium. Two magnificent Warhound Titans and the Companions, three hundred select Custodes, stood an eternal vigil over this enormous room, for in it lay the kilometer-high Golden Throne, where the God-Emperor of Mankind had lay in a state between life and death for two hundred centuries.

Had anybody looked upon the broken, Warp-ravaged body that was once the Emperor of Mankind, they would have seen a single tear make its way down his withered cheek.

It is the 51st Millennium. The Imperium of Man, having once stood supreme, is
crumbling. The Emperor, entombed within the Golden Throne, is dying. As the
Tech-Priests of the Mechanicum struggle in vain to prolong his life,
the light of the Astronomican is slowly being extinguished, leaving
humanity vulnerable to horrors of the Warp, and isolating countless worlds.

The innumerable souls of humanity look to the past, enviously beholding the
glories of the 41st Millennium, when the Imperium was crumbling, but still
mighty. The time of the Great Crusade has all but passed into the realm
of myth. For if the Imperium was ever so mighty, how could it fall so far?

Across the galaxy, Imperial forces are besieged, as the legions of Imperial
Guard and Astartes cry out for reinforcements, only for
their pleas to go unanswered, as there are no reinforcements. The forces of
Chaos, lead by Abaddon the Despoiler, overrun world after
world. Entire star systems are consumed by the Tyranids, or exterminated
by the Necrons.

It is the 51st Millennium. It is the twilight of the Imperium…