Principle of magic.

Disclaimer :I don't own the fate series.

An :This story is extremely Au with many events changed and altered.


Prologue.

The rain was pouring mercilessly from the dark grey clouds soaking the ground and the plants, leaving puddles all over.

Thunder striked, illuminating the interior of a beautiful mansion, standing in the middle of nowhere.

The gates of the mansion were closed shut, not a single sane person ventured outside at such a whether.

The thunder cracked again, illuminating a dark robed figure approaching the mansion.

Arriving to the gates the figure knocked with a gloved covered hand.

The figure waited for a moment before knocking again and this time the oaken doors swong open, reveling a young man his grey eyes scanning the visitor critically.

"Yes? How may I help you?" the man asked, his voice cold and aloof.

The person under the hood smiled "William Alstreim I presume?" it's voice feminine.

"Indeed, and you are?" he asked, his voice suspicious.

"My name is of little importance lord Alstreim" the woman said quietly "However if you need to refer to me as anything.. Call the the fifth magician".

Her words calm and collected as they were made the man freeze.

"T-The fifth!?" he exclaimed in surprise "Please come in milady, we better speak inside" he said moving aside as to let her pass.

The woman didn't say anything else, walking inside, her wet cloak dripping water on the polished marble floor of the mansion.

The owner didn't appear to care much, instead he closed the gates with a flick of his hands and moved in front of her.

"Please come this way" he said "We'll speak in my study" he said.

They walked up a flight of stairs and through deep corridors until they arrived in front of a heavy wooden door.

Putting his hand on the base of the door, the Alstreim let some of his prana to flow into the door which glowed for a moment before opening before the two.

Turning to the woman he smiled lightly "Please come in" he said.

The magician nodded and walked in, her eyes quickly glancing around taking every detail from the heavy oak table in the middle of the room to the few portraits of the previous heads of the family and finally to the bookcase filled as it's name siggsuggests with countless books.

She approached the table and took the seat closer to the exit, her host taking the one behind the table.

As they did the young man's relaxed demeanor vanished, replaced by a serious expression.

His hands on the table, fingers crossed he looked intensely at the hooded woman.

"So?" he asked "What brought you here?" he asked "I doubt it's my company you're seeking" his voice was emotionless, hiding his emotions.

The woman didn't take off her hood, but her mouth twitched into a thin smile.

"Indeed, although I have to point out that I find it fascinating that you believe my tale" she said.

The man smirked "I have my reasons" he said.

The woman decided not to pry deeper into the issue, instead she looked up, her eyes focusing on the man's face, her blue eyes seen through the hood.

"I won't beat around the bush" she said "I am here to offer you something.. Something that I am sure you'll really appreciate" she said quitely.

The man's expression didn't change, but his brow rose up in question.

"Oh?" he asked.

The magician smiled slightly and took something out of her cloak and put it on the table.

Carefully the man took the object and examined it closely, some kind of package wrapped carefully.

He slowly peeled the wrapping paper and stopped frozen.

There in his hands was a heavy book he knew quite well.

With trembling hands he opened the book and looked in, his breath hitched.

Instead of the numerous pages that should've been there he found a few crumbling and old pages, many looked like they were burnt.

Without a word he got up and approached the wall behind him, sweeping his hand over it.

The wall lightend up and released a hidden compartment, quickly reaching in he took a book with identical cover, only much fuller and much heavier.

Breathing in relief he put it and closed the compartment before turning to the woman.

"What is the meaning of this?" he asked, his distress reflecting in his voice.

The woman smiled sadly.

"This mister Alstreim is your book.. Or what was left of it.. It took me so long to track the pages you see before you" she sighed "I tried to understand what happened to it.. And in my investigation I arrived back at your time" she explained.

His eyes widened "I still didn't finish the book" he said quietly "But if to track what happened to it you had to arrive back here.. Does that means it was lost in my own lifetime?" he asked, now truly distressed.

The woman nodded "More than that.. You lost your life as well" she said quietly "It was believed that whoever killed you took the book.. However now I am more inclined to believe that he simply tried to destroy your life work" she said quietly.

The man's eyes bulged "You can't be serious, why would anyone... " he trailed off before shaking his head "So you've come all the way here to this uninhibited island just to help me save my life and book?" he asked unsure.

The woman smiled lightly "Something like that" she said "Your book is filled with knowledge that is invaluable.. Even in the future" she said quietly.

That stopped him in his tracks "Wait" his voice had a weird note to it "Do you mean to tell me that no one in the future was able to discern the true nature of the aether that now fills our world and how equally powerful it is to the 'grain'?" he asked.

The woman smiled wearily.

"Unfortunately we aren't exactly in a situation we can compare the two unlike you who've seen both elements, we call the 'grain' true aether" she said quietly.

To her surprise the man burst into fits of laugh "True aether?" he asked his amusement twinkling in his eyes "That's the stupidest thing I heared yet" he said "After all they are not just two unrelated elements but are actually antithesis to each other".

The magician nodded in interest "Please elaborate" she asked of him.

"Well in short I theories that the grain is the element of the gods, the element that defines their being just like aether is humanity's element, which is why we humans are not really part of Gaia's reality marble" he explained "My book mostly explores the difference between the two and explaines it in simple words".

The woman nodded but said nothing.

Taking it as a cue to continue the man did not dissapoint.

"Simply put, the gods and in extension the grain is the element of constancy just like the gods are unchanged so is the element that comes from there which is why they all had a role, for example war or love and so on" he took a breath before continuing.

"Humanity on the other hand is different. We aren't defined by certain aspects but rather posses the ability to change, we strive to concur everything around us, be it other people or the world itself. Or in other words aether is the element of change. For example take fire for example, ever heard of cold fire? That's the basic idea" he smiled his eyes burning with passion.

"However it's strength is also its weaknesses, since to use more unchanged abilities will take more energy and it will be much cruder" he finished and closed his eyes.

The woman was shocked, her eyes under the hood were wide as she listened to the man's theory.

"Wow" she said "This is quite something, I wonder who is responsible for killing you? Do you have enemies?" she cupped her face with her hand.

The magus's face turned serious "While I don't know who specifically it is, I have a pretty good idea for their motives" he sighed "Those idiots calling me a heretic and a traitor" a small bitter smile spread on his face "Taking their fury on me since they can't take it on old Gil".

"Gil?" the woman asked surprised "As in Gilgamesh? What connection do you have to him?" she asked curious.

"Does it really matter?" he asked but explained nonetheless "Gil is smart I'll give you that, but he doesn't have the necessary knowledge to pull something like the end of the age of gods by himself, I had my reasons to end it and so I provided him with the knowledge and he did the deed, now I am hunted since they are too scared off the guy to do even try to challenge him" he explained before shaking his head in dismay.

"I guess that no one else thought about researching aether itself thanks to those idiots"

That really put the woman into a stupor "You!?" she asked surprised "You devised a way to end the age of gods?!" disbelief in her voice.

The man nodded wearily "Sure, it wasn't all that difficult since they were already weakened by Velbar" he confirmed.

The woman shook her head firmly, she really needed to stay on track, she'll be able to hear more about this enigma of a man after she'll save his life.

"In any case we should really think about how to save your life now" she returned the conversation back to the correct path.

The man sighed "Don't worry about it, now that I know that my life is in danger I will be able to defend myself" he said quietly before lifting his hand and snapped his fingers.

The magician felt something washing over her and extending over, possibly as far as the entire island.

"I would expect of someone in your position to be more awere and keep your guard constantly up" she said a hint of mockery in her voice.

The man just smiled "This island should be hidden to anyone, it seems I was overconfident, I won't make this mistake again" he said.

"How long will it take you to finish your book?" the woman asked.

"A few weeks I guess, are you planning on sticking around?" he asked, brow raised.

The woman smiled lightly "Sure" she smiled dazzlingly.


A young woman her hair raven black walked through the underground halls of the clock tower a small smile on her face.

She looked down to the letter in her hands and checked the directions written there.

She turned to the right and through the door and found herself in a long corridor littered with doors on both sides.

"The second last on the right, ?" she mumbled as she approached said door only to stop in her tracks.

Loud noises were coming from the door to her left and she couldn't help but stop and listen.

"Richard" came a male voice "You've really outdone yourself this time" the voice was young and calm but Rin couldn't help but shiver.

"Not only did you brake into my office and tried to steal some of my research, but you somehow managed to destroy a family heirloom, you really are incompetent" the young man said.

The woman gulped lightly but stayed in her place listening.

"Please my lord!" the other man apparently Richard begged his voice cracking "I am sorry, please have mercy!" the man begged.

"Mercy?" the younger voice spoke again "You should've thought about it before barging into my office! It's not like you don't know the rules of the clock tower" the voice halted.

"However I will give you a chance to save yourself Richard" the younger man said in a calm voice causing the girl to shiver.

But the man apparently didn't catch on to the danger he was in.

"Thank you my lord" the man said "Anything you want" relief was evident in his voice.

"Good, than meet me tomorrow at the enforcers training hall at ten sharp" the man said before his footsteps resounded and the door opened reveling him.

He was a young man of about nineteen with short black hair, his eyes as gray as storm clouds.

Noticing the girl standing in front of his office the young man smiled pleasantly.

"Good day miss, are you waiting for me?" he asked with a warm tone.

The woman shook her head "No sir" she said quietly "I was told to report to the second last on the right" she said flushing in embarrassment of being found out eavesdropping.

The man's eyes brightened in curiosity "So you're the new student Zelretch was talking about?" he asked in wonder "It is a pleasure to meet you" he said extending his hand "I am Corvus Alstreim".

Rin stopped in her tracks "A-Alstreim?" she asked "As in William Alstreim? The author of the principa Magica?" the man was a legend after all, his single book was like the Bible for magi, she herself read it a few times.

Corvus smiled "Sure, he is my ancestor" he said before he glanced at a chained watch on his belt and paled.

"Bloody hell it's late!" he exclaimed before turning to Rin "I am sorry but I have a lecture in three minutes and I have to run, how about we meet up later today? Let's say around seven pm?" he asked.

The woman nodded in understanding "Sure that sounds lovely" she said before walking to the old man of the jewels office.

And only as she entered she realized she never gave him her name.


End of chapter 1.

More detailed explanation at how exactly everything works will come in the coming chapters.