A kind of addition to my previous work The Stained King, dealing with an Artoria who was summoned as Berserker instead of Saber (Since there's a Lancer version). I think there is a good chance of her being summoned as Berserker, probably for similar reasons why Saber Alter exists. So, this may be a full story, if I get enough inspiration/interest, but it might just cover parts of Fate/Zero that we see with Kariya and Berserker. So, this is the summoning of the spirit.

Enjoy.

Chapter 1: King's Judgement

Camlann, circa 500 AD

It wasn't a legendary battle at the end, nor was it an epic clash of swords.

Father and daughter exchanged only four blows between them, enough to settle and finish the story he'd written.

Watching metal slide into the traitorous knight, Artoria Pendragon felt nothing. Blonde hair, blue eyes and that smile were reflected on her opponent's face.

Her daughter's face.

She had warned Mordred; warned her that she was not ready. Her death sealed that fate, and stopped her reckless rampage just a little too late.

Did she really think she could rule Artoria's Kingdom with this?

Picking the legendary sword from the ground, she swept it down, removing the enemy leader's head from her shoulders. It would have been good to pick up the child's head and show everyone the price for treachery, but those who would have cared were long since dead. Putting her foot forward, the King stumbled at the lightheaded feeling. Her heart was beating so loudly, blood pumping from adrenal, that only when it had abated did she feel something was wrong.

Warm blood flowed over her probing fingers, gravity helping the precious lifeblood pour from her wound.

But there was no pain. Artoria laughed, but she wasn't happy either. A mix of emotions ran through the ruler's tired mind and she collapsed forwards onto the mound's side. Arms tried to lift her up, but weakness prevented even that small movement.

A King did not die with her face to the ground, thought Artoria, and used the last of her strength to roll onto her back. Hark, look; the evening sky cast red light on the corpses around her, the once noble and proud land reduced to a killing field.

Small and intermittent, her laughter soon gave way to a berserker's sobs, fists clenched in anger. It wasn't fair. IT WASN'T FAIR! Why this way? Why die like this, surrounded by dead friends? It wasn't right, it wasn't a King's death.

As her eyes began to flicker, a last burst of anger gave power to her vocal cords. "Traitors!" Crows and ravens scattered in the shout, but she didn't stop there. "Traitors, all of you! May this Kingdom be cursed! May your happiness turn to sorrow and your glory turn to shame! I shall never forgive this betrayal! I shall, never, forget" The proclamation ended with a whisper, her last image the sky of death.

Matou Mansion

Uncomfortable, unpleasant, unnerving, the white haired man didn't feel like himself at all. Inside his body crawled all manner of foul things, but far worst than them were the crest worms eating away at his life.

Kariya Matou was now just a mere vessel for the old man's greed; but if it meant saving Sakura, the reluctant Master would go through Hell. Gritting his teeth, Kariya raised his hand and began the chant Zouken beat into his mind. Magic poured into the room, making Kariya feel for the first time that his goal was in sight. Such power could only come from a superior spirit that was worthy of his rage.

Yes, his rage. He raged at Zouken for putting him in this situation, raged at his brother for his weakness, and he raged at the magic that cursed his blood. Kariya hated that Sakura had to suffer, that he'd been too late to save her completely.

It was always the same; they suffered because of him.

Ignoring the gleeful aura from the old man, the haphazard Mage pushed with everything he had to bring forth the spirit from history. Memories flashed into his brain; the clashing of swords, the cries of war, and the inevitability of it all.

The brutal landscape of a civil war.

Old, forgotten incantations burnt his throat as he began the next part. Words of power transformed into chains of a binding rage, his life itself drained to support what would come. Muscles strained as the rest of his power wrapped around a spirit from this battle.

A warrior was what he needed.

A white light, the purest, blinded him just before it turned a sickly red. Kariya almost collapsed then, but continued standing against the lack of breath and energy.

Tarnished silver armour and a black corroded, smoking blade seared themselves into his mind. The sword gave off a sickly red glow that surrounded its wielder. Her eyes, a piercing black with red sclera, were surely beautiful once, but were now merely a demon's. He knew instinctively this spirit was a woman of the sword even without the giant, onyx metalled sword. A blackened confused him for a minute until he put it all together.

A battlefield of blood, a great betrayal, and the fall of a King; despite the physical evidence, this was none other than King Arthur Pendragon. "TRAITORS!" roared a guttural voice, deafening to the watchers present. Her attention latched onto them, piercing gaze causing Kariya to cringe away. "WHICH OF YOU IS MY MASTER?"

She walked out of the circle, sword held up high. "WHICH OF YOU IS MY MASTER!" Zouken kicked Kariya forwards so he bowed at her feet. Trembling, he stuttered out the final requirement.

"I, I, I am Ka-kariya Ma-matou. I, I am your Master. I command-"

"You dare? YOU DARE COMMAND THE KING OF KNIGHTS?"

"Keep your servant under control, Kariya. Goodness, you are such a disappointment."

Kariya felt her anger zero in on the figure behind him saw the sword cut him diagonally across, legs and chest separated. Blood trickled from his own cheek where the attack had glanced him and he looked back at the collapsed body in fear.

The Master whimpered, unsure what to do as he turned to look at the servant. "The stench of evil lingers. You!" She pointed at the Magus. "There is evil in you. It must be ERADICATED!"

"NO!" yelled Kariya, jumping up and staggering away from the sword's slash. If he died, Sakura was doomed, and Tokiomi would win. Only one thing to do. "By the power of my Command Seal, I order you: Kneel before me" Emboldened by Zouken's death, the shout rippled through the air and cut through her loud screech of hatred."Kneel! I am your MASTER!"

Her knees slammed into the ground, head glaring with such hatred that the little confidence he gained wilted. No, he had to stay strong, had to command this spirit who existed only because of him. "I am not evil. Look into my thoughts; see why I fight!"

The mental connection was fierce, and Kariya felt blood pour from nose. The Servant's rage was eldritch and corruptive, with more than 1000 years preventing completely understanding. Her search was a grasping and prodding procedure with his memories laid bare. She found his deepest, darkest desires, things even he had only suspected and hid away under a cover of decency.

Kariya Matou was laid bare before her judgement and a quiet moan came from his tilted head, the Master not even bothering to look at her memories. Once done with stripping her Master bare, the Servant let him fall back. In the silence, he was more scared now than he'd ever been in his life. "Permission to speak, my King."

An imperceptible nod conveyed her consent, and Kariya took in a deep breath. "A miserable specimen as myself would never dream to claim superiority over a knight of honour." The words came from his terrible, wasted life of a story. Where it came from he did not know, but his Servant had peered deep into his min to the point she would know when he lied. "But, to be summoned you must have a wish like me. We can let our desires come true, just like how I desired the old fart's death and you helped me with that. I have many more, as no doubt do you. My King, accept me as your vassal, so we may gain what is ours!"

Where was this strength coming from? Since the old bastard's death, he felt like a different person, like he could actually do this. Did his father really have such an effect on him? Did he really matter that much? In the end, his body didn't belong to Zouken or himself. It was Sakura's, through and through, and it was for that smile that he knelt in submission.

She stalked up to him, sword raised up as she spoke. "You… I despise your kind." He flinched as if slapped, keeping his tongue silent before this immense air of dominance. "Like all men, all you desire is women, and everything you do is purely because of that." Kariya closed his eyes, a tear dripping from his right eye.

But the death knell did not come, and he dared to look up. "You protect the weak, but only to gain the one that you think belongs to you. However! A King must weigh his judgements carefully and selfishly!" Berserker walked past him, sheathing her sword with a clink. "For the sake of that girl, so innocent and pure, I shall deign to lower myself and accept your servitude."

"I let cowardly, self-serving knights inhabit my court, so I can tolerate this kind of degeneracy." Her foot kicked him forwards, Kariya sprawling against the wall and facing the violent Servant. "Hear now your King's decree: You shall refer to me as Berserker from now on."

A black gauntlet grabbed the front of Kariya's collar, Artoria dragging the Master across the floor against his struggling."You will explain it all to me, and by God Himself, if you waiver in your devotion my wrath will be clear" she warned, ignoring the struggling Kariya's protests.

This was nothing like he imagined.