uyuki City, Sometime ago.
"Goodnight, Onii-chan." Illya mumbled as she wiggled her way into the futon she shared with her younger brother.
"Good night, Illya." Shirou stroked the young girl's hair as she slowly drifted into the night's sweet embrace. Until just a few weeks ago she had been an energetic child whose every facet moved at the speed of light. But now, all of that energy seemed to have leaked from her body, leaving her sluggish and depressed.. Gone was the girl who had tackled him every morning and would always refuse to let go afterwards and in her place lie a shell of a person who could barely wake up in the morning. So depressing was her downward spiral that Shirou had not slept a full night in weeks as a singular thought lay heavy on his mind: Illya was going to die and there was nothing he could do about it.
For a boy who had devoted his entire life to saving others even as he sacrificed his own well-being, it was too much to bear. He had saved so many people by ending the Grail War yet he couldn't prevent someone so close to him from dying an untimely death. Though no one judged him for Illya's fate, there was nothing he could do after all, but Shirou would not let the matter go so easily. For weeks, as Illya's life slowly drifted towards its invertible fate, he, and Rin on several occasions, had read endless texts on magic scrounged from the depths of what remained of the Einzbern's castle, yet none of them were of any use. Indeed most agreed on a single fact: homunculus were entities created for a single purpose and then discarded once that purpose had been fulfilled. In all actuality, it was amazing that Illya had lived as long as she had. To seek to prolong her life was a Fool's Errand at best.
And for that reason Shirou resolved to do all he could for Illya in the twilight of her life. For weeks he had attended to her every whim. From eating out to simply sitting together and watching television, if Illya wanted something it was the least he could do to carry out her wishes. Among these was wanting to sleep near Shirou. Though he felt strange sharing his sleeping space with a girl, it would mean that if anything happened over night, that he'd be there just in case.
"Good night, Illya. I'll see you in the morning." Shirou repeated himself once more to his sleeping sibling, all the while hoping deep in his heart that those words would become truth.
***
"Illya wake up. If you don't get up soon we'll be late for breakfast." Shirou gently shook his sister's small frame, hoping to rouse her to the waking world. Despite his best effort, there was no response. It was odd to say the least, as Illya was never late for the mornings first meal.
"Illya, come on!" He shook her once more. Still no response. "Illya...?" His voice quivered. Moving his hand into postion to check Illya's pulse Shirou's expression soon contorted into one of absolute fear. There was no pulse. She wasn't breathing.
Illyasivel Von Einzbern was dead.
For a long moment Shirou sat, his mind devoid of thought as he stared as his sister's fallen form. This couldn't be happening. Just last night they had eaten dinner together, she had laughed at her favorite anime, she had kissed him goodnight...
"Dammit! Dammit! Dammit! I should have done more..." Shirou cursed no one but himself. He was the one closest to Illya, he could have done more, read just a few more books, just tried harder. Then maybe none of this would have happened. He, who considered himself a champion of justice above all else, fell to his knees as tears cascaded from his blood-shot eyes. He had failed Illya, he had failed his father, he had failed himself and the ideals that defined his very being.
In that moment, cradling his sister's unbreathing body close to his heart, he silently renewed a vow he had made long ago.
***
He dashed forward, his curved dual blades poised to strike his foe in the chest. One thought lay on his mind; "this man must die." A henchmen of the local crime boss whom had been responsible for the deaths of dozens. To bring him to a swift end -to do justice to all that he had wrong- was the right thing to do.
A moment later the man-in-red's blades found home, slicing open his target with surgical precision. Despite the man's best effort to the contrary, blood spilled forth from the open wound like a waterfall, staining his clothing a deep crimson. Soon he would be dead and justice would finally be served. As his target struggled against death itself the man-in-red smiled. This was what he lived for. To bring an end to those who would harm others and save as many people as he could in the process. Long ago he had ceased to be the hopeful child that fought so valiantly to end a pointless war, in the present he had become an embodiment of the very concept of justice. To right wrongs was all he lived for.
Dismissing his projected blades, he set off to return to the house in which he had been staying, leaving the fate of his victim to the very same people he once subjugated.
His room was nearly empty and more then a bit desolate, containing only a bed and simple dresser that had both began to rot ages ago. Not that it mattered, he didn't mean to stay here long anyway. Despite his grandiose title, he was little more then a mercenary for hire. A man who wandered from town to town protecting the innocent and destroying injustice in all its forms. Such a lifestyle had made him many an enemy, making it dangerous to linger in any one place for too long.
But for now, sitting in the half-rotten bed and staring into the endless night sky, he would rest, Here, away from the bright lights of the big city, one could see thousands upon thousands of stars twinkling in the heavens above. And it was on nights like these that his thoughts always returned to the night Illya died. He could recall in brilliant detail the feeling of her small body as it lay limp in his arms and the intense sense of failure that had gripped his heart as a result of it.
He had always wondered, if Illya could see him now, what she would think of him. The brother she had known was a kind young man who went out of his way to help others. He was a wanderer who was constantly covered in the blood of sinners, a fry cry from the boy he once was. He imagined she wouldn't even recognize him now. It was a shame, even though her death had spurred him to become the man he was today, he had completely abandon the parts of himself that she had loved so much.
Rummaging in his pocket, he found the picture of her he had always kept on his person. It was a simple shot taken just after the war's end. In the background lay the expansive manor they had shared in those last days while before it stood the boy he once was, Illya, and a girl with long black hair tied into two pony tails. They were all his friends, people who had stood by his side through thick and thin. Gazing at the crumpled photo and the white-haired girl smiling back at him, the man once known as Shirou Emiya quietly wept.