Fate/Stay Night: Rebirth

Prologue

She thought she had died for a second time, her soul and consciousness were assimilated by the Grail and she found herself lost in visions she didn't want, but then came the light, the raw power that separated her from the Grail and she felt alive once again. She took the time to look at what was happening, her body had turned into the "cup" once she merged with the Holy Grail, but now the "cup" was broken with half of it missing, the leftovers of the remaining half were scattered all over the place, Kiritsugu was fighting to stay awake while looking with horror at the sky, looking up she noted the mud coming out from the Greater Grail pouring down to the streets of Shinto, just as the mud was about to touch her everything around her disappeared, turning her surroundings into a white ethereal space.

Once she could see again, she only recognize what was surrounding her as pure magic and knowledge, at first her mind couldn't comprehend what was happening, all of it was overwhelming, but as time passed her mind adjusted, what could only be described as a "little voice" on the back of her head told her something that left her perplexed: she was on the Root! And that excited her. She, Irisvel Von Einzbern, had accomplished what almost all the Magi in the world reached for: reaching the Root, a, for a lack of a better word, "place" of infinite magic and knowledge, the place that dictated all the things that happened and a place far beyond from the normal world. She had the hopes and dreams of magecraft in the palm of her hand and yet she couldn't do anything, at the lack of a body, either physical or spiritual, Irisvel only existed as a consciousness surrounded by the mysteries of the Root, but of course, a powerful and miraculous thing as the Root wouldn't let it stay that way. She didn't know nor understand how or why, but information began to flood her mind, information of the past, present and future, of the many timelines that existed, information of the mysteries, magecraft, time, space and souls. She didn't know how long that process took, she couldn't tell as the lack of any reference of time made it impossible to measure, but in the end there was nothing of magic or magecraft that remained as a secret to her, even the five true Magics laid nude in her mind.

This newly found knowledge helped her to understand just how wrong the magus were about the root, about the magecraft in general. Even those who called themselves users of the true Magics were wrong about them, they all thought they were a way to reach immortality or the Root, and well it was true, but it was just a half truth, in their most basic sense the five Magics were designed to ensure and protect the existence of the "world" and it's multiple phenomenon, but as the magus were selfish and fool creatures they were unable to comprehend them and thus, they were only able to lern parts of just one Magic. And in truth, Irisvel wasn't so different, the only thing she truly wanted to do with her new powers was to see what had happened after the destruction of the "cup", to know what had happened with her husband and her daughter.

Using the second magic she returned to Fuyuki just to presence how a fire that had engulfed Shinto was dying due to the heavy rain, a man of black hair and dressed in a black suit was desperately searching for something or someone in the debris, finally the man stopped on a specific place, using all his available energy the man moved some debris, murmured something with a broken voice and then carefully lifted the body of a boy of auburn hair and golden-brown eyes, slowly the kid's eyes closed and the man noticed how the boy seemed like he had stopped breathing, acting quickly and without a doubt the man summoned a sheath that Irisvel recognized as Avalon and introduced it into the boy's body, she couldn't help but smile, of course Kiritsugu would take so drastic measures to ensure the life of an innocent boy.

Just as Avalon was placed inside the boy's body everything stopped for Irisvel, right before she could wonder what was going on vertical cracks appeared on her vision field, at the same time various sounds assaulted her ears all of them were the voice of her beloved husband, some were joyful, broken, saddened, angered, the whole spectrum of emotions. Looking around, visions presented themselves in-between the cracks, all of them showing all the outcomes from what she just saw, in some Kiritsugu took the child to a hospital, in other the kid rejected Avalon and died on Kiritsugu's arms, in other the mud surrounded them and Kiritsugu killed the child with his own hands. She couldn't understand why, but Kiritsugu's decision to save the kid fractured the timeline and created different "routes" for the kid's life, using the second and fifth magics, Irisvel watched everyone of the routes, taking a special interest in four of them. The boy's life was... Complicated to say the least, after being adopted by Kiritsugu, thing that actually didn't bother her, though it did bother her that Kiritsugu abandoned Illya. The kid inherited his wish to be a hero of justice, but that ideal, added up with a severe survivors guilt complex, made the boy think his life was only worth it if he dedicated it into serving everyone else.