Prologue
"Rin, I'm not so sure this is going to work." Shirou said with skepticism as he set another gem filled with his od on a point of a five pointed pentagram. It wouldn't be the first time Rin set him on an impossible task with one of her foolproof plans, only for things to go horribly awry. Sure, he always managed to so cope somehow or other, but he'd rather not be in trouble at all.
This whole set up seemed sketchy and built off of more guess work than he was comfortable with. That didn't mean he wasn't going to do it. Following her plans would only probably hurt rather than definitely.
"What are you saying Emiya-kun?" Rin stood up haughtily from where she was writing a complex Rune on the floor and flipped her hair out of her face while smiling sweetly, "I double checked all my formulas for this mystery. You just have to play your part and everything will work out, right?"
Shirou winced at her scathing tone. She had worked day and night for months going over every detail of her formalcraft notes to make this work. And that wasn't mentioning all the gems this experiment would waste, as they were already full of his od. It was long past the point where he could simply say 'no' and come out of this with his manhood intact.
He sighed, hung head, and decided to get this over with. After all, whats the worst that could happen? "Alright, fine. But you have to get out of range before I begin. It's my reality marble, so I don't think it will hurt me even if things don't go as you said, but I don't want you anywhere near even if it manifests."
He felt her pat consolingly on his arm and could practically feel her arrogant smirk. "Don't worry, Emiya-kun. I won't be anywhere near the inside of your soul. I'm sure you have all kinds of dirty secrets you want to have a chance to hide first, after all."
"It's not like that Tohsaka." He grabbed her arm and turned to face her. "I just want you to be safe."
Tohsaka's face flushed a under his direct gaze. "O-oh..." She turned away from him in a huff. "Of- Of course you idiot! Obviously my own safety is my first priority! Just... I'm going over this one more time, just to be safe."
Shirou smiled as Rin once again worked him through the steps of her plan. Rin really was a good person. But eventually she ran out of things to check and said a terse goodbye. Shirou sighed again as he stared forlornly at the formalcraft drawn over the shrine floor. It was time to bite the bullet.
After discovering that he had the beginnings of a reality marble, Rin had been insistent that they study everything that they could about it. He had spent countless hours simply meditating and studying poetry and shamanism to try to bring it out, with minimal success.
The self actualizing aria itself was more or less complete. The problem was he had no real way to test it. Summoning a reality marble was a very prana intensive process and his reserves just couldn't cut it by itself. The two of them had considered a mana transfer, but in the end concluded that the first attempt should rely solely on his own od for optimal results. Not to mention he was very insistent that Rin was nowhere near him for the actual manifesting, so she couldn't be there in the case arise he needed more prana.
And that left him with this. Five small gems painstakingly filled with his own od all placed on a formalcraft circle designed by Rin that was loosely based on Casters use of the Ryuudou temples leyline.
The theory was sound, if he ignored the small fact that modern magi couldn't directly access a leylines mana and all that was between him and mana poisoning, or worse, was five small gems and Rins formalcraft.
No sweat, right?
Standing in the center of the pentagram, Shirou let the trigger go off in his mind and began his chant.
"My body is made out of swords." He could feel all twenty-seven of his magic circuits flaring with od, then processing ambient Mana into Prana.
"My blood is of iron and my heart of glass." Just as the strain began overheating his circuits the pentagram below him began to glow with blood red light.
"I have overcome countless battlefields," The air became thick with mana as it was drawn from the leyline below Ryuudou temple and released into the air.
"Not even once retreating," Just as planned, the gems absorbed the overflowing mana to mix with his stored od. A thin stream of prana then flowed out of each gem toward him, dissipating just before reaching his body as the energy became available for him to use.
"Not even once being victorious." Ripples started to form in the air as the effects of his bounded field began to exert his existance on reality around him.
"The bearer lies here alone, forging iron in a hill of swords." For one of Tohsaka's projects, everything was going almost suspiciously right. The formalcraft was working perfectly and he could feel his reality marble just out of reach.
"Thus, my life needs no meaning." Then the flames that rewrote reality manifested on the horizon and began to flow towards him like an unstoppable tsunami...
Eh? Wait wait. shouldn't it be the other way around? And he wasn't finished yet? No. No time for second guessing. Stopping now would be catastrophic. And now that he thought about it, Rin never actually told him how to turn this thing off anyway. So he did the only thing he could and cast away his doubts and continued his aria.
"This body is made out of infinite swords." A surge of Mana came out of nowhere, rushing into him and cracking all Rin's gems. That surge of energy pushed him over some sort of tipping point. Prana was leaking from his circuits at a rate he never thought possible, but now that his aria was over he could focus on other things.
Which was good, because Shirou, quite frankly, was confused. The world around him had faded away to reveal a barren hill of swords.
"If these flames were my reality marble, then what was that?" Was all the time Shirou had before the tsunami of fire washed over him and the dome of flames that was his reality marble.
~"And so the blood of the world mixed with the blood of a soul.
My blood, intertwining with yours, let our fates be shared."~