Long, long time ago.

At the Age of Gods. When human and other magical beings were still living side-by-side with "Truth", Magic was something considered common as present days' magecraft. The miracles produced by Magic was not something rare, as Magi could directly access the [Root] – the fountain of Knowledge and Truths to create said unnatural phenomenons (Mystery) called as miracle. 

However, since the twilight of Age of Gods and the rise of Age of Man, the world's direct connection with the [Root] was also severed, and magi lost most of their power. Along with the advancement of science and technology, numerous Magic lost their Mystery as their miracle could be reproduced by science. Like creating fire, even without Magic, human could already realize it by lighting the match. 

For those Magic who already lost their Mystery, they were reduced to a mere craft – called as magecraft. 

However, even then, the remaining magi didn't lose their drive. They remained in their path, seeking the lost "Truths", and desiring to reach the [Root].

Eventually, some magi managed to arrive at the "Truth", creating new miracles in this Age of Man. Those new miracles were called as modern Magic by present magi, while those Magi who were able to use Magic were honored with the title of Magician. 

According to Ryan's knowledge from the wiki, in the hearsay, it was said that the beginning First changed everything, the following Second acknowledged many, the resulting Third showed the future, the linking Fourth concealed itself, and the final Fifth already lost their meaning.

First Magic – Denial of Nothingness, it was some sort of Creation Magic. Its previous user had long died, while its current holder was unclear, or perhaps they had yet to exist currently.

Second Magic – Kaleidoscope Magic, its domain was Operation of Parallel Worlds which allowed its user to travel between parallel worlds. Its user was the Second Magician – Kischur Zelretch Schweinorg.

Third Magic – Heaven's Feel, the domain of this Magic was materialization of the soul. This Magic was once possessed by Einzbern Family, but they had long since lost its true Mystery. The best they could do now was to produce an incomplete Third Magic (not cost-efficient).

Fourth Magic, its details and holder were unknown.

Fifth Magic – Magic Blue, its use and effect were unclear. This Magic was currently possessed by Aoko Aozaki, the Fifth Magician.

Sixth Magic – this Magic was only hypothesized to exist, at the same time it had yet to appear in the world currently. 

The domain expertise of Einzbern family was alchemy and homunculus creation. Even compared to other magi lineage, the Einzbern could be said to be the forefront on this field. However, since they lost the true Mystery of Third Magic, they had been focusing their research on recovering that insurmountable peak of Mystery again, reclaiming their past glory once more.

At some point, the previous head of Einzbern family, Justeaze Lizrich von Einzbern, had come to realize that their family's own effort was insufficient to actually reproduce their lost Third Magic. 

She then decided to cooperate with her two colleagues who similarly desired to realize the Third Magic, namely; Nagato Tohsaka – the previous head of Tohsaka family, and Zolgen Makiri – the previous head of Makiri family. 

Einzbern family provided the alchemy to create it and prepared the vessel for the Grail. 

Tohsaka family provided the necessary spiritual land and called forth the Servants. 

Makiri family assembled the magecraft to stabilize the starting materials and designed the Command Seals that command the Servants. 

These three magi, witnessed by the Second Magician – Kischur Zelretch Schweinorg, started up the grand ritual on the site which would later become Fuyuki City. 

The said ritual itself later would be commonly known as "Holy Grail War" ritual; wherein seven pairs of Master and Servant would be fighting each other to determine the one worthy to realize their wish. 

Of course, there were some inside stories to this ritual, but it's a tale for another time... 

In the first and second Holy Grail War, there were no definite winner as there were some accidents which eventually causing all participants to die or the Grail was unable to descend. 

At the Third Holy Grail War, Einzbern family decided to arbitrarily tweaked with the ritual, intending to summon strongest Servant to win the Holy Grail War. They summoned Avenger – Angra Mainyu, dubbed in the legend as All the World's Evil. 

Unfortunately, their expectation fell short as Avenger was unexpectedly weak. He was killed shortly after the Holy Grail War had just begun. 

However, Avenger's true ability lied not on his personal power, it actually lied on his conceptual value; as the amalgamation of All the World's Evils. The existence of Angra Mainyu who was considered an amalgamation of evil wishes managed to corrupt the Holy Grail – which was a wish-granting device – when he was defeated, and being absorbed into the Holy Grail. 

The Fourth Holy Grail War, which Kiritsugu participated in two years ago, ended with the great catastrophe after an unworthy Master managed to reach out to the corrupted Grail. It was also at that time that Ryan transmigated to this world. 

As of now, Ryan was quietly training to prepare himself for the upcoming Fifth Holy Grail War which would happen around eight years later according to original timeline. 

However, from what Black Iri had said few weeks ago, Ryan began to doubt whether his information about the future to be relevant enough to his current world. 

Even Black Iri could notice Ryan's peculiar origin, so it was not that hard matter too for other peak existences in this world to notice his existence. 

With their silence, Ryan was unsure whether they had malicious intention to him or not. What he was sure of, however, was that he needed the strength to protect himself. The kind of indomitable strength to achieve what he wanted to do in this world. 

And, if it was possible, he also wanted to reach out to… 

"Ryan, I don't know what kind of mystical thing you are practicing, but now you are already halfway in your path to materialize your soul. With the help of Einzbern's incomplete Third Magic, combined along with your mystical practice, you have the highest chance to actualize the highest Mystery of all magecraft, a true Magic – the Third Magic. Isn't it amazing? It's the dream of countless magus! 

"Join hands with me, Ryan. If you do, I can help you to get all what you want! Including myself if you prefer~ 

"Or do you want my daughter? Perhaps, you want both of us together? 

"Hey! Hey! don't ignore me, Ryan!" 

Currently, Black Iri was flying across the room as she watched Ryan silently practicing his Arcane Art. 

Perhaps because she was previously bored and could not show herself due to suppression of Ryan's Mystic Eyes, but now that she had come into an agreement with Ryan, she became bolder by appearing more often into outside world. 

Though, only Ryan could see her as her existence was more like a ghost spirit. It was not impossible for other people to see her, but they must have higher spiritual sense than most magi to do so. 

"Can you be quiet already, Avenger? I am trying to concentrate here. If you dare to make another pipsqueak again, I will silence you roughly." 

"…A gag-order play?" Immediately after saying so, Black Iri quickly returned back to the black shard before Ryan could react. 

Ryan could still hear her giggling as she watched him became speechless after her teasing. 

'How could she know those kind of words? Did Kiritsugu have some strange hobbies back then…? Or did the Grail also cause that kind of perviness corruption?' Ryan could not help but thinking like that. 

Nowadays, Black Iri had been staying cozily inside the black shard as she watched Ryan's daily life and training. From time to time she also boldly appeared in outside world to tempt Ryan into joining hands with her, promising various benefits to him like a saleswoman. She had also already started helping Ryan to absorb more spiritual energy from the area, though she also did 'small' modifications to Ryan's magic circuit in doing so. 

Ryan turned a blind eye to her little trick as her action was in line with what he wanted. 

It was because at that time when Ryan advanced his Demon King Solomon's Arcane Art to level 3 – Enshrined Soul, the mysterious spell diagram on his soul altar was also completed. From its completion, a knowledge of new mystic art then became available to Ryan. 

Although Ryan did not have the chance to try his new mystic art due to his current lack of proficiency and strength, the existence of that mystic art itself had opened more ways for Ryan to strengthen himself. 

What Black Iri did now would only make his plan go smoother in the future, so why would he stop it? Though she didn't know all this and just did her trick in secret, thinking that Ryan was unaware to her plan while also continuously tempting him with herself. Seriously, although she had been corrupted by the contaminated Grail, with her naivety, she was really not suitable to be an evil villainess… 

Black Iri had once wanted to destroy his soul altar because she seemed to feel that its existence was encroaching upon the Third Magic which the Einzbern had been painstakingly pursuing. If Ryan managed to actually materialize his soul with the help of his soul altar, without threading the path Einzbern family previously walked on, it was not impossible for the authority of true Third Magic to change hands toward Ryan. That was probably what she had on mind back then. 

Although, now, after realizing she could not do anything about it, Black Iri tried to tempt Ryan to join the Einzbern family through her. At least, that way, it would look like the Einzbern family still managed to recover its glorious history once again by recovering the lost Mystery of true Third Magic. 

Ryan looked up to the night sky. There were countless stars lighting up the sky. Up above these stars, there was a lone domain separated from the time axis which had been monitoring the world since beginning of time. That place was the convergence of innumerable heroes and legends who rose to prominence from the mythical era until the distant future. 

As long as this world and humanity existed, so would they.  

The Throne of Heroes. 

Gaia and Alaya. 

The [Root]. 

Just by thinking on them, rather than feeling resigned at the shadow of their omnipotence, Ryan could feel his spirit blazing furiously instead. It felt like the exciting sensation when he defeated that old bastard had returned to him. 

He realized that his recent calm life had been too enjoyable that he relaxed himself unconsciously. 

He still remembered his wish to that unknown goddess at the last moment of his previous life. 

After gifting him such incomprehensible and mystical Arcane Arts, she would not expect him to just stay still and living an ordinary life, would she? 

Otherwise, it would only be a waste giving him such precious chance after all. 

'Since I have arrived in this world, there's nothing wrong to try battling it out with this world's powerhouses, is it?' 

Of course, the prerequisite for such action was that Ryan had to ensure that he had the ability to back up his ambition. Otherwise, if he lost his life in the process, it would not be worth it. 

. . .  

"Yo, seems like he has realized something about it. As expected of my proxy. I will be waiting up here, catch me here if you can. Ha Ha Ha Ha~" 

At a certain Celestial realm. A young woman was laughing cockily while looking at the mirror hanging in her private room. Other people might only see a bunch of foggy images in that mirror, but thanks to her connection with certain someone, she could see past the confusing fog to look at the real images shown inside it. 

She was wearing thin piece of almost transparent clothing, revealing most of her voluptuous and youthful figure as she squirmed slightly on her bed. Her private parts were merely hidden away by a layer of soft silk, evoking a sense of wild imagination for any onlookers–if there were any to begin with. 

"My Lady, there is another mission from the Upper Management. It is about an escapee from Netherworld Prison. The Nether Emperor has already asked for our assistance." 

A respectful voice sounded from outside the woman's room. 

"Huuhh... Just when I began to relax... Can't they send another person to do it!? Hey, tell me why, little Cia?" 

"According to what I heard from our superiors, do forgive me my Lady, but it seems only my Lady has the spare time to do this mission." 

"..." 

Aren't you just saying it's because I am too idle, Alicia!? Grr~ Argh~ I still want to watch him... Wait a bit, I will be back soon, my dear proxy! 

. . . 

The time had passed since that one time when Ryan had multiple breakthroughs in his practice three years ago. 

Since that time, Ryan had been training more arduously than before, tempering both his body and skills as a magi everyday. Some times he even stayed up all night to research on how to expand his arsenals. 

He also spared some of his time to practice kendo with Taiga, though it was almost a complete beat-up for him at every session. However, all those beating finally bore fruit. At some point, because Ryan already started winning in several small kendo tournament within the city, his name was getting more renowned within the circle as an upcoming kendo prodigy, rivalling Taiga Fujimura's early fame. 

His school life could be considered monotone. He had been ranked first in each years from Elementary school to Junior high school–since all he needed to do was repeating basic knowledge he had already known. Even if there were some differences in the basic knowledge, Ryan was able to quickly make it up with his enhanced perception. As of now, Ryan was already 13 years old. He was attending Homurahara Junior high school as the first year this year. 

Shirou had also grown up to be a more cheerful boy. He liked to help with the chores in the house, as well as helping the neighbors if there was a chance. He was quite well-liked in the neighborhood. 

In these three years, life had been going peaceful and smooth for the Emiya Household, especially Ryan and Shirou. 

Although,... the same could not be said for Emiya Kiritsugu. 

His condition was getting worse, his body was getting weaker along the years passed. His accumulated injuries and Avenger's curse had slowly robbed him of his life by the day. 

Even if Kiritsugu somehow managed to fool the others, he could not hide his condition from Ryan. 

At a certain night, after having dinner, Ryan, Shirou and Kiritsugu were sitting together at the veranda, they were watching the cloudless night sky together. 

The moon was especially bright tonight. 

"...once, I had a dream to be a hero of justice." 

Kiritsugu looked at the moon, his eyes gazed at the far side as though he was seeing through the passage of time, to that years when he was still a spirited youth. 

"Why 'once'? So, you are not anymore, father?" Shirou looked at Kiritsugu with his curious eyes. 

Hearing what Kiritsugu said, Ryan felt a jolt as he remembered a certain memory. 

It's probably around this time... so, it has finally came... 

Ryan was looking at Kiritsugu with complicated gaze. 

"... unfortunately, yeah. Because after I became older, I realized that my dream was merely a childish dream. 

It was hard to call myself a Hero of Justice any longer. I should have realized it sooner..." 

"Oh, what a pity..." Shirou looked slightly sad. 

"Indeed, what a pity..." Kiritsugu had a sad smile as he looked at the moon. Images of his life since his childhood until his recent life seemed to flash in front of his eyes at that moment. 

"Since you can't become a Hero of Justice any longer after you became an adult, then I will continue it, father. 

I am still a kid after all." 

Shirou was smiling brightly as he looked expectantly at Kiritsugu. 

Startled by what Shirou had just said, Kiritsugu turned to look at Shirou. 

His eyes glimmered with appreciation and relief, as if a burden had been lifted from his heart. 

"Ah,... fine. 

"...I am glad."

With a relieved look, Kiritsugu spoke kindly to Shirou, then he turned to look at Ryan who had been unusually quiet this time. 

"Please look after Shirou in the future, Ryan." 

Kiritsugu said as he smiled at Ryan. His gaze was silently imploring Ryan to not let Shirou make the same mistake as him in the yesteryear... 

Ryan wanted to say something. But, his words were stuck in the throat, he was unable to say it. After few seconds looking at Kiritsugu quietly, Ryan finally spoke, 

"...I understand, father." Ryan replied firmly. It was also his promise to Kiritsugu. 

Now, Kiritsugu felt at peace as he looked at Shirou and Ryan. His gaze eventually wandered to the bright moon up above the night sky, he felt that his life finally also had a meaning... 

"The moon sure is beautiful tonight..." Kiritsugu muttered calmly. 

Few days later, Kiritsugu took his last breath. He passed away calmly, leaving with a smile on his face.