I don't own Fate. Fate is the property of Type-Moon, and no financial gain is made from this or is sought. This is for entertainment purposes only.

Guardian of Zero

Prologue

Something was wrong. The summoning went right, both her Noble Phantasms were with her, and all her knowledge was intact. But something was wrong…

…ah, there it was. The connection with her Master was tenuous, as though it was made of gossamer and would break in an instant. Why? That should not be the case. The summoning went right, and it wasn't like…

...please don't tell me it's him….

The answer thankfully was no, it wasn't him. The Servant's eyes widened at the sight of the panicky girl with a bleeding hand cowering on the floor before her, and then narrowed at the sight of the stooped and black-eyed man gaping at her a good distant from them both.

Damn Alaya…

But then again…even if this wasn't exactly what she had in mind, it did fit her agreement with Humanity's collective subconscious. And she never was one to let opportunities pass whenever they appeared before her. She smiled, and Zouken's eyes widened as she drew one of her Noble Phantasms and stabbed him in the heart, all in the blink of an eye.

"Jeweled Sword of Zelretch…" she whispered, and the blade flashed once before it ripped Zouken's body apart.

It won't kill him. But it will buy time.

Even as she slid the oversized piece of jewelry back into its scabbard, she was already turning and moving with all the speed a Servant was capable of towards Sakura who screamed once as she was pulled into the stranger's arms. "…calm down…" the Servant whispered to her as they blurred up the stairs and burst through the doors. "…I'm not going to hurt you. I'm going to get you out of here, and take you someplace safe."

Sakura fell quiet and closed her eyes as the Servant swept through the house. "Cleansing flames…" the Servant whispered, a ball of flame coalescing in her free hand. "…heed my call, and purify these tainted groves."

Clutching her Master closer to herself, she jumped through a window and across the grounds. As she leapt over the fence, she twisted in mid-air and hurled the glowing orb of blue flame at the Matou mansion.

Burn in hell, maggots!

Sakura screamed again as she heard and felt the explosion behind them. Abruptly she felt the older woman holding her land, and set her gently down on the ground. She opened her eyes, and found herself staring at a bespectacled woman with black hair and blue eyes. She looked…she looked like her mother.

"Mama…?" she asked.

The woman's eyes widened and then she smiled sadly before shaking her head. "No…" she said before brushing a lock of hair away from Sakura's face. "…I'm not your mother. I suppose you could say that we're related, but that's beside the point. You may call me Caster."

"Caster…?"

Caster nodded before standing and turning to look at the burning mansion behind them. "It won't kill him…" she whispered. "…if it were that easy he'd have died long ago…"

Sakura shivered, remembering the pit and the lifeless touch of her 'grandfather'. She stepped closer to Caster and hid behind her. She looked like mother, and she said they were related. And Caster saved her. She was a good person…right?

Caster looked down at her and smiled knowingly before picking her up and beginning to turn away from the burning house. "…don't worry…" she whispered soothingly. "…I won't let anything happen to you, I promise."

"Really…?"

"Yes, really…" Caster replied, and took another look at the burning house before taking her Master to safety and jumping over the skyline of Fuyuki's suburbs. The girl clung tightly to the Servant, but Caster's mind was on another concern, specifically her prana supply. Sakura barely had enough prana to summon her, and she didn't doubt that if she didn't find another source of prana soon, she wouldn't last until noon the next day.

That would be bad.

Caster paused in her flight, balancing atop a telephone pole while gathering her thoughts. In the distance Matou continued to burn merrily, but the flashing and whining of fire trucks could already be heard. She wondered if the other Servants had been summoned yet, and swallowed dryly.

As a Caster-class she was formidable, but she needed preparation, time, and material to make full use of her strengths. However there was also the fact that she was only a Counter-Guardian, and not a true Heroic Spirit; she would not delude herself into thinking that she could truly match the real thing on her own if push came to shove. And currently weighed-down as she was, if she were attacked now…

That would even be worse.

She shook her head. No…not after everything she had gone through…she would not fail her sister again, not after killing her with her own hands, and not after selling her soul to Alaya. Caster spared a glance down at Sakura, who'd fallen asleep.

Exhaustion probably…she has incredibly minute prana reserves by this point, and they'd probably been drained summoning me.

She smiled slightly at the thought that Sakura was able to summon her as a mere child, but set it aside. She had to find another source of prana and fast, and then setup a hideout before more enemies showed up.

Caster swallowed again and wondered if she should just look for and assault some poor sap as a source of power. It would leave a sour taste in the back of her throat but then again…she was a Counter-Guardian. She'd done worse things in the name of Humanity, even if she currently couldn't remember the details.

And then she remembered, her eyes turning to Mt. Enzou and Ryuudo Temple. If that witch could do it, then she should be able to as well. Smiling with satisfaction and tucking her sister into her arms, Caster continued leaping over Fuyuki towards the mountains.

Caster tucked the sleeping Sakura into the futon provided by the monks in their shared room, and then quietly stepped out of the room and into the open. Sakura was safe for now, but Caster knew that she'd have to tie up loose ends sooner or later.

Zouken Matou was probably still alive and kicking and even if he wasn't being protected by a corrupt and mindless puppet that her sister had been turned into, Caster just knew that killing him wasn't nearly as simple as it sounded. And there was their father…Caster clenched her fists in anger. Oh that one would definitely be getting it for all the grief that he'd caused her, Sakura, and even that fool Shirou.

Kirei…that one was dangerous. And together with her father…Caster shook her head and began to walk towards a quiet corner. With preparation and time she could confidently face either Kirei or her father with minimum difficulty, but the two of them at the same time was something else entirely. And right now the two of them spent a lot of time together, the bastards.

"I am one born to command power." Caster whispered, the words of her aria stirring her magic and crafting a magic circle around her feet in light. "All things bend to my will, and the five elements answer my call. Sky and earth shall not deny me, nor shall the things that live in this world. Thus by my command: come, life-blood of the world!"

The circle flashed, and Rin Tohsaka smiled as she was lit from below by the light of magic, and felt her prana reserves begin to fill. It would take time, but if she did this regularly then she would only have to worry about resources.

Ah well, it wasn't like it would be the first time that she 'requisitioned' supplies. And this time it would be for a greater cause. As for the other Servants, she would just have to observe for a while, and perhaps make an alliance with one of the more reasonable Masters. And Sakura…well, she'd sold her soul to Alaya to save her, and to give her what should have been hers.

Caster returned to astral form to optimize the prana flow and reduce the strain on her still-low reserves, and began to outline a training regimen for her sister. She also wondered what her younger self was doing right now, and wondered whether or not to intervene in her life.

I was so pathetic at the time, looking up to that worthless fool. Hmm…I wonder…

A/N

That's it for the prologue, but this is my first fanfic so be gentle please!