All the usual disclaimers. I own neither Warhammer Fantasy nor RWBY. This story is for entertainment purposes only.
The dark hallway filled with the light clanging of metal armor sliding and shifting as the column of warriors, knights, and wizards followed after their emperor. Karl Franz strode forward at their head, his face held high and his polished plate gleaming even in the low light. Belying his dignified posture, Karl's face was grim, showing the truth of his thoughts. The emperor went to his doom.
As the large company of picked men and one woman finally came to their objective, the Altdorf bestiary, they could see out over the walls of the city. All around the capital of the Reich stretched the vast forces of Chaos. Great siegeworks lay about in various stages of construction. Enormous hills of flesh rose and fell as scattered giants slumbered. The target of this night's mission was a collection of large tents and banners deep within the enemy's mass: the encampment of Archaeon the Everchosen, champion of Chaos Undivided, Bringer of the Apocalypse and Herald of the End Times. The collection of ramshackle huts was a far cry from the organized headquarters of and Imperial General, but each man it contained was leagues apart from any general's bodyguard.
That was the reason each knight and soldier was picked for their skill at arms first and foremost. The two wizards amongst them were Carmella Kristoff and Leggard Dynst, a bright wizard and celestial wizard respectfully. Both were senior member of their orders and had unparalleled control over their schools of magic. It would be desperately needed as their magic would be the barricade keeping the Chaos forces from overrunning the small band. As much as Karl wished he could bring more wizards, there was simply no more room and every man would be needed to defeat the Everchosen's bodyguard.
The war party gathered around the four griffons left in all of the Empire. While each massive beast was monstrously powerful, there were only so many fully armored men that could ride along before they wouldn't get off the ground. That limited the party to a Captain renowned for his dueling skill, the two wizards, a warrior priest of Sigmar wielding a massive great hammer, the Witch Hunter Captain of the Altdorf Chapter house, eight knights of various orders, the Emperor and the three other griffon riders. As there was no hope of them making a second trip, the three griffon riders were also skilled combatants themselves.
As Karl stood beside his old mount, Deathclaw nudged him with his beak. He reached up and stroked the griffon's head whispering, "Yes old friend. You know don't you? Well if this is to be our last ride together, let us make it such a ride as to be remembered for an age." The massive animal's eyes sparkled somberly as he spoke.
Turning to address the humans, his voice rose, "Tonight we ride to spit in the face of our doom. The enemy surrounds us, their numbers are beyond counting. Beasts and monsters follow them in the thousands and tireless daemons flow through the warp. Any hope of holding back their coming assault is far beyond us. I do not speak of these things so as to waver your spirits, I seek only to remind you of the import of what we do tonight. There is no other path open for us, so secret fall back to retreat to. Our one single chance is to strike at the heart and the head of the enemy host in one blow! Tonight, Archaeon must die! Nothing short of this is acceptable. No retreat, no surrender! Slay his camp and raise the bastard's head on a pike!" A guttural roar from his followers greeted his speech.
As Karl looked around, he could see the fire in their eyes at this final chance to hold back the enemy tide, even if it was long odds. A defiant spit in the eyes of their great foe, and it was little more than a spit to be sure. In his private thoughts Franz couldn't help but wonder if successfully killing Archaeon, no simple feat in itself, would even lead to an overall victory.
Historically the death of the horde marshal would send a shock rippling through the enemy ranks that could be exploited into a rout. This time seemed different. The great enemy had not possessed the same level of ferocity before, nor the same unwavering steadfastness.
In the end, it did not matter. Karl was not lying when he had said this was the only option open to them. Therefore it was the option they would take. Were it any other foe, a full nighttime assault would have been devastating after the shock of losing the commander. Yet with the men and beasts of Chaos, so close to their final victory, Archaeon's death might spur them on to greater feats of courage and barbarity if the gates were to open.
The decision had been made then to wait, let the infighting and squabbling break what little cohesion they had, before sweeping them from the field. It would mean grave danger to the emperor and his companions. In fact it had been a serious point of contention for many in the inner circle of the emperor. Most prominently the Reiksguard. Their objections had been for naught. Karl Franz refused outright to send men into so dangerous an attempt at the last ditch, without leading them. He only hoped this would not all be in vain as he mounted Deathclaw.
Twenty minutes later, the assault group was flying under a dark, heavily clouded sky. The griffons were unarmored to reduce the noise and allow for more of the heavily weighted knights. The humans meanwhile, had cloth wrappings around every joint to cover their own small noises. They had begun the night's journey by flying high above Altdorf before setting off in a gentle glide towards their destination. The belief being that there would be far less risk of the great wings alerting a sentry and sounding the alarm.
With their altitude and uninterrupted line of sight, it was possible to see just how far and deep the mass of men and monster alike stretched before them. Several awed and horrified mutterings started upon Deathclaw's back only to be silenced by a look from Karl and the griffon both.
The wind rushed past them as they descended towards the camp of the bastard they aimed to kill. Feeling not unlike a bird of prey, Franz smiled ferociously as they neared the camp. They were almost upon it when they suddenly realized they were losing too much momentum and would certainly fall short of the camp by some meters. With a nudge of their thighs the griffon riders directed their mounts upwards. Nearly as one, the great beasts gave several wing beats before resuming their glide.
Unfortunately, this did not go unnoticed and soon there were several shouts of alarm from beneath them. Deciding speed was worth more than silence at this point, Karl waved forward to the other riders before pushing Deathclaw forward into an aggressive dive.
They rapidly picked up speed and barreled into two Chaos warriors as they emerged from a hide shelter. Hitting them with all the force and subtlety an angry griffon can possess, quite a bit of the former and very little of the latter, one man's midsection was pulped underneath a claw and the other's head ripped off by the great beak. Leaping from the saddle as the last of the riders fell off from wherever they had been clinging to, Karl pet Deathclaw's side whispering "You did well, now help the others."
One of the men accompanying him, the champion of the Golden Lions order quipped "Hell of a landing sir. I had to piss fore al that but I reckon I'm good now." Carmella barked out an ashy laugh while Franz smiled and said, "I'll buy you a bottle of Altdorf's finest to replace your lost fluids Lysander." The man seemed to perk up at that and saluted before storming off to engage an emerging foe.
Carmella looked at Franz asking "Should I raise the wall yet sire?" Glancing around the camp as fires lit and men moved towards their position, he gave her a nod and she immediately went to work raising a wall of living fire that would encircle Archaeon's camp. Franz noticed Laggard beginning to call up a great storm to keep the heavens clear of enemy flyers. The knights and various other warriors were engaged or moving to engage the members of the Harbinger of the End Time's retinue.
Carmella's conjured fire created a bright backdrop against which the fighters became mere shadow puppets. These were far more detailed than those that Karl's father used for bedtime stories. He doubted even the nimblest fingers could have made figures such as these. With a final somber reflection that he would never get the chance to make shadows dance for his unborn grandchildren, he moved on.
Searching the figures for his prey, he found the beast clad in mortal flesh. Archaeon watched the battle around him, his expression unreadable underneath the three-eyed helm. His posture was slightly clearer, seeming to indicate total relaxation amongst the bloodshed. Undoubtedly feeling the emperor's gaze upon him, the helmeted head of the Great Destroyer slowly turned to regard the mortal man who dared defy him. The bright red eyes glowed malevolently, seeming to pierce him with their concentrated hatred.
With no more words, the two leaders began to advance towards each other. Shouting a bloody warcry, Franz sprinted forward several steps before being forced to leap out of the way of a fireball. Bringing his warhammer above his head to block a downward strike, he received the shield to his unguarded side. Staggered he back stepped to give himself room. The Chaos lord was coming at him fast, and he only had moments to duck beneath the slash and hammer the shield out of Archaeon's hand. The warrior of chaos was hardly fazed and gave Karl a snapkick which sent him reeling back. The Chaos blade came screaming in at him; the only thing that stopped him from being split in two was the Silver Seal, a magical ward that could protect the wearer from mortal blows.
Even so, the blow drove him to a knee and with a sharp cracking noise the ward broke. With a ferocious roar, he lunged out and shattered Archaeon's knee. He got a response in way of an agonized bellow of pain out of the dark warlord. Smiling, tasting victory, Karl sprang to his feet and brought his hammer down on the man's weak guard smashing the sword from his grasp. The dreadful warrior rolled away from the following hammer blow and scooped up his shield while rising on his good knee. He caught the next swing on the shield and punched the Emperor's nose. Karl Franz glared though the pain and unleashed a brutal series of blows against his foe. The daemon forged metal began to bend and warp around the arm that held it.
However, as Karl brought his hammer above his head to break the shield and arm together in one almighty blow, a blinding pain erupted in his torso as a sickly blade emerged through his chest. Covered in the sick of Nurgle, it wept a viscous mixture of his blood and pure plague liquid. Just as suddenly as he had felt victory close at hand, he saw it snatched away. His body felt increasingly cold and his strength fled. He slowly collapsed as Archaeon rose, laughing. "Well little Franz, I'll admit, I underestimated you. And it almost cost me. But it looks like my warriors were more than a match for your weaklings." With what little strength he had left, Karl cast his eyes back towards the rest of his men. He owed them that much at least. It was a gruesome sight. His men had been butchered to the last. They had been hacked apart and their corpses were now being used for the barbaric rituals of the Chaos Gods. The Chosen of Nurgle who had stabbed him stared down slack jawed, the feverous eyes glowing madly. Karl Franz did the only thing he could muster and spit in the eye of the smelly warrior. Getting no response, he turned back to Archaeon. The horde master was now fully risen and had retrieved his sword again.
Limping back to the fading emperor, he leaned down so they were face to helm and growled out "My only regret is having to kill you before your city burns. But I will not let you breathe my air." And so saying he brought the mighty daemon blade in a massive overhead swing that cleaved Karl from his neck to his groin, and the Emperor was no more.