Prince Charon said:
His plan, IIRC, was to kill himself in order to prevent himself from becoming a Counter Guardian.á So, he wanted to change history.á If he still shows up, even though Rin doesn't use the gem to heal Shirou, that means that his plan won't work.
Considering that he wasn't erased from existence the instant Shirou died, it's a pretty sure bet his plan failed, right?
Anyway, a continuation of your original snippet, Charon. Probably not perfect, but readable I think.
*********
Emiya took a deep breath as he contemplated his work. He'd used the previous months to prepare himself as best as he could. Forcing this body to assimilate his fighting skills, training the circuits to handle his magic, discretely gathering informations on his opposition, all that and more. Tomorrow, Bazett Fraga McRemitz would come to Fuyuki together with her Lancer and open the first act of this War. Before that happened, he needed to be ready and that meant performing the last and most critical part of his planning: summoning his Servant.
So here he stood, in the shed in the backyard of the Emiya household, where Kiritsugu had first summoned his Servant and where a fool had stumbled upon a miracle which had saved his life. A life he had wasted in the most ridiculous way.
But not this time.
This time there would be no need for a miracle. He'd carefully traced the summoning circle, chosen the time and prepared the incantation. Here too, he was as ready as he'd ever be.
Just one last step.
ôTrace, on.ö He chanted, but rather than turn toward the hill of his soul, he focused on this body and the treasure hidden within.
He'd pondered the question for a time but in truth there had been no other choice. Saber was by far the best Servant he could hope to summon and so he needed the appropriate catalyst.
Emiya Shirou himself had been it in the original timeline, his foolish mentality overlapping enough with the King of Knights' ethics that she'd answered his call.
But he was different. A twisted existence such as him would without a doubt repel her from beyond the ages.
So, instead he'd fallen back on her sheath. Not the real one though, its abilities were too good to discard unnecessarily, and there was no need for it. He was absolutely confident that, just in this case, he could create a perfect copy. The only perfect copy he'd ever achieve, his greatest projection.
Even as it was, a loose mass of magical energy spread across this body, he could still see it perfectly whole, not even the littlest detail missing. And as he carefully Traced the image in his mind, he gathered the material from this body of fire and steel and then brought them together into reality. There was an intense flash of light and then...
Perfect.
Satisfied, Emiya put the sheath in the center of the circle and began chanting again in earnest. There was no time to waste. Certainly the copy was perfect now, but soon the World would recognize it for the fake it was and corrode it. Before that happened, he needed to perform the summoning.
It was easy. Unlike Rin, he was at his best at the critical times, when his tension was so high it cleared his mind. He endured peacefully the fire that burned him, shrugged off the way his senses went haywire. All that was nothing in comparison to what he had endured.
And finally the shed was bathed in light once again, the command seal engraving themselves on his hand, and she appeared.
Perfect, he thought.
Then something he couldn't see pierced his chest.
For an instant the surprise eclipsed the pain. He blinked and suddenly his sight was filled with her face.
ôSab-er?ö He couldn't understand. This was Saber. Even now as his vision grayed he could have recognized her among thousands. Then...
ôWhy?ö
His heart tightened as he read the pure disinterest on her face. She wrenched her sword away from his body mercilessly, cutting him nearly in two.
And then he noticed the anomalies.
ôShirou...ö
It wasn't his sight that was fading, Saber was really deathly pale. And her armor...
"... You should have killed me when you had the chance.ö
It was black.
As she advanced on him, he couldn't help but laugh as hard as his destroyed chest could manage.
ôA distorted Servant for a distorted Master.ö He whispered. "How fitting."