I don't own Fate/Stay Night or RWBY.

Note: This story contains spoilers for F/SN Heaven's Feel route. Continue at own risk.

The cavern glowed with unnatural light as waves of magical energy rolled off the giant artificial structure at its centre. The Holy Grail War was at its end, with all seven Servants now dead.

Emiya Shirou limped his way up to the great device. His eyes had lost their light and his body was now slowly breaking apart from the magic that ran uncontrolled within it. As he slowly turned his failing eyes up to gaze at his final objective, broken memories of the War that remained in his mind came to the surface.

He had been given a choice. To save the one he loved, or to save the countless innocents. One course of action would lead him closer to his goal, his dream of being the Hero of Justice; the other would require him to throw away everything he fought and strived to his entire life. So Emiya Shirou made his decision and threw away the ideal he inherited from Emiya Kiritsugu, the man who saved him.

Shirou's arms slowly rose from his sides, stopping just above his head. As they moved, unnatural scratching sounds could be heard from within, like metal grinding sharply upon metal. As it was, he was now literally made of swords. The very blades that made up his inner world were now the cause of his death as they manifested uncontrollably from within his body and tearing him apart from the inside.

Rider had been cut down by the corrupted Servant of the Sword. One single lapse was all that was needed, and the blackened blade had brought the Servant of the Mount to her death. Shirou stood alone in front of his former Servant, Tohsaka Rin having gone to confront Matou Sakura and prevent the birth of Angra Mainyu.

Their fight had been interrupted by the arrival of a heavily wounded blond man who radiated the same power as a Servant. Shirou did not recognise the golden man nor was he able to fully process the hate-filled words he gave to the blackened Saber; his mind already damaged from overusing the arm of the Servant of the Bow that had been grafted in place of his own. Yet Emiya Shirou perceived and understood the nature and identity of each and every sword that the unknown Servant manifested, storing them into his personal world. Despite the sheer scope of the power held by the golden man and the golden chains he used to temporarily bind Saber, his injuries were too great and he too fell to that black blade, cursing the world with his last breath.

The intervention of that golden man was a fortuitous one. His waves of Noble Phantasms had succeeded in weakening Saber Alter and giving Emiya Shirou the opening to deal the final blow. As she faded, Shirou thought he saw a gentle smile gracing the lips of the pale girl and deep emerald eyes gazing into his own in a final farewell.

Blue light formed in his hands, taking the form of the golden blade of the King of Knights. It was an imperfect copy, one that bore only a fraction of the true power that the original weapon could deliver.

But it would be enough.

Weakened as it was, the Sword of Promised Victory was still a Last Phantasm, forged by the planet itself and imbued with the very wishes of mankind. The Greater Grail was not an object that could withstand the might of the sword that was held in the grip of the boy, imitation that it was. Golden motes of light emerged from the ground around him and rose into the air on an ethereal breeze. The gentle glow from the light formed a sharp contrast with the dark, malignant energy that was resting within the cradle of the Greater Grail.

Emiya Shirou stood ready, his body upright with legs apart and planted firmly in the ground. He stood not because he could, but as a result of the blades impaling his body from within holding him together. The last remnants of energy left his body and flowed into the blade he held above him, poised and ready to strike. Unbidden, one final memory sprang up within his fragmented and dying brain.

Emiya Shirou reached the place that Rin had been fighting Sakura in an attempt to reason with the girl. Now there was no fighting, but only the broken body of the older sister held in the arms of the younger. The younger girl looked up as recognition and humanity entered her blood red eyes. The tears flowed unabated as she smiled at the person who had fought and thrown away everything for her. She opened her mouth and her words cut into his heart sharper than any blade ever would.

"Please kill me."

Emiya Shirou could not accept that outcome. In desperation he searched through the weapons he had, but could not find even one that would prevent the birth of the Servant Avenger. All seven Servants had been killed and if channelled through the Lesser Grail that was Matou Sakura, the world would be destroyed by the malicious evil that even then was waiting from within the Greater Grail for its eventual birth. He lacked the ability to stop that, to cut the connection between the girl and the dark entity in the Greater Grail.

"Please, Shirou. Don't let me do this. At least…I want to die as a human. Please…end this nightmare for me."

The girl's pleas shattered his heart. His resolve wavered as the tears sprang up in his own eyes. Whether it was their planning or their strength, it had been insufficient. That Saber Alter had been defeated proved inconsequential. The deaths of Matou Zouken and the priest that had orchestrated the events so as to bring about the birth of Angra Mainyu amounted to nothing. They had still failed to accomplish their objective.

And so Emiya Shirou made his decision.

Death could not bring salvation, but now it was the only thing he could provide the girl before him. The end of the pain and despair she was living through would be his final gift, the only thing left within his power to give. Yet as the blade pierced her chest, a radiant smile crept onto her lips as she thanked him for saving her.

In life, neither of the sisters had been able to live happily together, forced into opposing families to fight for an object that could grant only destruction and suffering.

In death, they were now in one embrace, forever holding on to the other for eternity.

Arms of steel swung down as magical energy burst forth from the Holy Sword. Emiya Shirou was now empty as he completed his final stroke. He no longer had anything left to protect in that world. He had already discarded his ideals for a cause that ended in failure. Physically and emotionally, he was empty.

But there was at least one last thing he could do. Emiya Shirou would rid the world of the evil that lay in the Grail, permanently erasing it such that it would never have a chance to be born on the Earth. In his final moments, he would at least save the world from that possibility.

"Ex-"

He mouthed the word more than he said it, straining his body to push the name out in a metallic whisper.

The wave of light rose to engulf the Greater Grail and All the World's Evils.

"-calibur."

The light grew and filled the cavern as the eyes of Emiya Shirou came to a close.

0-0-0

"Well, well, this is certainly not something you find every day."

A voice that sounded like that of an elderly man reached his ears. Emiya Shirou opened his eyes to see a world of white. There was nothing at all no matter where he looked. Turning down, he realised that he could not even see himself. A hearty laugh resounded from somewhere in that vast space.

"Don't worry yourself over that. I'm just here to talk."

Shirou blinked. He could not see the speaker. A more pertinent question rose in his consciousness. "Am I…Am I dead?"

The silence that followed was broken a moment later as the voice replied. "Not exactly. Or perhaps it's better to say not yet. I am curious as to how you came to be this way, boy."

"I destroyed the Holy Grail." Shirou replied simply as the answer came naturally to him. "It would have spawned something that would end the world, so I just stopped it."

"Hmm. Yes, that thing." Somehow the voice sounded aggravated. "After centuries and not only did those idiots fail to get their little ritual to succeed, they somehow managed to fill it with that hideous thing in the process. I suppose it's better off gone after what it ended up as."

Shirou got the distinct feeling that the owner of the voice suddenly turned towards him with renewed interest.

"And you, boy, was able to destroy that tainted cup. For someone of your age that is quite the amazing feat."

"I'm still dying."

"Yes, there is that," The voice dismissed Shirou's comment almost carelessly. "But just hypothetically speaking, if you were not dying, what would you do?"

Shirou sighed. "I have nothing left to live for even if I did survive," He replied.

"And why is that so?"

"I discarded my dream in order to save the person who meant the most to me. But I failed to save her in the end. Everyone else who helped us died as well. There is nothing left."

"What was your dream?" The voice came back after a pause.

Shirou did not know why he was speaking so openly, especially to someone whose identity he did not know. But the lack of pain and the slight return of sensation in addition to the knowledge that he was about to die must have loosened some of his prior inhibitions. Regardless, it was not information that would harm anyone, so Shirou saw no reason why he could not give an answer to the honest question. He smiled sadly in reply. "My dream was to save people. I wanted to be a Hero of Justice."

Shirou heard a laugh. It was a soft one and held no malice or contempt. Just a simple acceptance of the answer he had given. "That is a rather unusual dream to have, boy. But certainly it is not a bad one. I've known of far worse dreams a person can have."

"What good did it do?" Shirou whispered. "The end result would not have changed regardless."

"And so you threw it away. Do you despise that dream now, boy?" The voice was sombre.

Shirou shook his head after some thought. "No, I can never hate it. The desire to save someone can never be a bad thing. It will always be a beautiful ideal to strive for, but that is all that it is: an ideal. It is impossible to save everyone. To save one meant that I had to let another die. And I refused to let the one I loved die, even if it meant putting her ahead of the countless innocents. But in the end, I failed to save even that one person. I failed because I was just not strong enough. That's all there is to it."

Shirou felt his consciousness start to fade as darkness began to creep up in the corners of his vision. He felt no alarm at it. Maybe it was not that he could not feel it, but that he just no longer cared. Shirou felt a tugging in his being that, much to his own surprise, he identified as regret. After a moment, he recognised why he felt that way. Despite the irony behind it, he felt that it was fitting that such an emotion would be the last thing that the man known as Emiya Shirou would ever feel in that situation.

"Ah… Maybe there was one thing left. A regret."

"Oh?" The voice sounded more distant as the darkness took over more than half his vision, but carried on it a tone of curiosity.

Emiya Shirou smiled wistfully. "Perhaps… Perhaps I just wished that I could have saved someone… just as how I had been saved."

A burst of laughter shook the world of white. It persisted for several seconds before the voice seemed to finally contain its mirth. "Yes, that will do." The voice returned with some approval. "Don't worry, boy. All you need to do is to hold on to that wish. Let this old man do the rest."

That comment was odd and carried with it an intensity that confused Shirou. Before he could ask what the voice meant by that, the world burst into a blinding kaleidoscope of colours that forced Shirou to close his eyes.

Feeling the last of his consciousness drift away, Shirou let the darkness take him.

0-0-0

Blink.

He opened his eyes, blinking them several times as his brain took time to process the impossibility that he was faced with.

'I'm not dead?'

He should have died after using Excalibur to blow up the Greater Grail back in the cavern beneath Ryudou Temple. Even before tracing the Sword of Promised Victory, his body was already at the end of its rope. Shirou had been warned that removing the Shroud of Martin would cause the magic within Archer's arm to invade the rest of his body and being only human, the magic of the Servant would be more than what he could handle. Yet he had done so to face off against a corrupted Berserker and Saber in consecutive fights. Him being alive should not even be possible.

A cold gust of wind brushed his cheek and he reflexively reached up to touch his face with one hand. He had his sense of touch again, Shirou idly noted. His entire back was against something cold and hard and he pushed himself upright into a sitting position and he froze.

There were buildings around him. The last memory he had was being in a cave that was far from Fuyuki, and now the place he was in did not even resemble the city he grew up in at all.

'Where am I? Did someone bring me out of the cavern of the Greater Grail? How did they even manage to heal the damage I sustained?' These questions and more raced through Shirou's mind as he looked around wildly, not seeing anything familiar to him at all.

It seemed that surprises were not over for Shirou as he glanced down at the hand that had been holding his face.

His left hand.

Shirou's eyes widened in shock as they travelled up and down the length of the arm from the hand up to the shoulder and back. The skin was light and lean-built, not at all unlike the rest of his body. Gone was the dark, tanned skin and hard muscles that made up the arm of the Servant of the Bow. In its place was apparently his own arm once again. His mouth felt dry as he swallowed nervously. He could feel a part of Archer's knowledge and battle experience within him. He even had access to some of Archer's more frequently used weapons. The rest were a blur but he knew without a doubt that they were there. Yet accessing the information imparted to him through the arm was not causing him any pain, nor did he feel the invasive push of the foreign limb's energy. For lack of a better description, the knowledge felt no more alien to him than his own.

Getting to his feet, Shirou looked around him. He did not yet have answers as to where he was, or how he had been able to survive, or how Archer's arm was no longer killing him, or how all the damage his body had sustained seemed to have miraculously disappeared. Emiya Shirou just shelved them with all the doubt and discomfort a person in his situation would feel, and slowly analysed his surroundings. If he had been brought to his current location, then the person who did so should be close by. If nothing else, he could at least discover who had fixed him up and where he had been brought to.

He did not recognise the city. The buildings were low-built and European in design, made primarily of brick and marble. It was a stark contrast to the glass covered high-rise towers that dominated Fuyuki's skyline. It was night judging by the black sky, and most of the shops that lined both sides of the street were closed. It had to be relatively late, as there were no other individuals out and about for as far as his eyes could see.

'Looks like whoever left me here does not want to me to find him,' Shirou thought as he gave up on trying to search for his rescuer after several minutes of searching for the presence of even a single person. Shaking his head, he decided to clear some other nagging concerns he had. Briskly entering a narrow alleyway between two buildings, Shirou moved as far into the shadow as he could. What he was about to do was not something he could allow to be witnessed.

"Trace on."

A familiar heat flowed through his body as his magic circuits came to life, the energy generated by his soul flowing at his command. Pulling on Archer's knowledge of their shared magecraft, Projection, Emiya Shirou reached into his inner world and pulled on the blades he was searching for. With a flash of blue light, the married blades Kanshou and Bakuya sat snugly in the palms of his hands. The familiar warmth of the grips provided him small comfort in a place completely foreign to him.

The weapons came to him naturally and felt no different from when he last traced them. That at least meant that his magecraft had not been affected by whatever had been done to him. The strain he felt every time he traced a weapon seemed to have lessened considerably but he ignored it for the more obvious and unsettling signs he noticed about the blades.

He could not feel any rejection or degradation on the blades.

Normally Gaia, the collective will of the planet, would reject phenomena that went against the natural order of things. Magecraft was a prime example as it comprised of transforming the world through unnatural means, and any ritual or spell that was cast would be subjected to a rejection from Gaia in an attempt to return the world to its natural state. That was the reason rituals and spells had to be constantly fed prana or else they would simply dissipate out of existence. For Shirou to be unable to detect any influence from Gaia bore many disturbing possibilities.

'This just keeps getting stranger and stranger. What the hell is going on? Does this location have a bounded field that lessens the effects of Gaia?'

Now that he was paying attention, Shirou could feel the denseness of Mana, the magical energy generated by the planet, from where he was standing. To an individual attuned to sensing magic, it was like breathing underwater with how saturated the place was with the energy. While he was not an expert on the subject matter, Shirou was certain that such a phenomenon could not be natural. Dismissing the falchions into blue motes of light, Shirou stepped back out onto the street. His attempt at finding answers only led him to even more questions.

Looking about, Shirou figured he might as well try to find out where he was. His eyes searched the place, unconsciously gravitating up towards the single object illuminating the night sky.

The moon.

Or rather, what was left of the moon.

The left half of the moon was still the same as he last remembered, but a large portion of the right side had been shattered, and the pieces floated about as though held in place by the moon's own gravitational force. The sight was so ludicrous that Shirou rubbed his eyes, pinched his cheek and even gave himself a slap just to see if he was somehow in a dream. To his horror, he was not.

"A…different world?" Shirou murmured in a daze at the revelation. Gaia's non-existent influence, the impossibly high levels of Mana in the atmosphere and the condition of the moon were a dead giveaway that somehow, he was no longer in the world he was familiar with.

Shirou's knees buckled as his strength left him, the weight of the situation surpassing what he was capable of handling. He collapsed back into a sitting position as he cradled his head in his hands. In less than a day, he had gone from stopping a manifestation of all the evils of the world and death by magic overload to somehow escaping death, having his injuries healed and being sent to an alternate world. This after he had lost everything he held dear, and no longer had the desire to live or a goal to fight for.

He let out a bitter laugh at what seemed to him like a cruel joke. For what reason would anyone choose to save a man who had no desire to be saved?

"Maybe there was one thing left. A regret."

Shirou stiffened. His memories were in a mess, but he vaguely remembered speaking to a person after destroying the Greater Grail. Being so close to death at the time, he had no recollection of who he spoke to, nor the entire specifics of what had transpired in that conversation. But Shirou remembered those words and the raw emotion he had felt at the time he said them.

The sound of glass shattering in the distance brought his attention back to the world around him. The world that was not his own. Several explosions followed and Shirou instinctively stood up and jogged in the direction of the sound. All this happened so quick that by the time he collected himself, he was already at the junction that led off to another street. Cautiously, he glanced around the corner of the building.

A short girl in a black and red dress was fighting against a group of men in black suits and wielding cleavers in the middle of the street. The girl was wielding an unbelievably large red scythe that was taller than herself, while fending off slashing attacks by the men by firing bullets from her scythe and using the momentum to land blows on them. She spun about at a speed that was difficult even for Shirou to follow, reminding him somewhat of the inhuman agility that Servants of the Holy Grail War had possessed.

A man in a fancy white suit and bowler hat that had been idly standing to the side and watching the fight raised the cane he was holding and fired off an explosive round powerful enough to destroy the section of the street it impacted, sending the girl careening back as the other men got into position around her.

Shirou tensed up as he unconsciously bent his knees and assumed a combat stance. A part of him was screaming to go and help the girl and he knew why, even if the knowledge left him with a bitter taste in his mouth. Deep down, the man known as Emiya Shirou could never ignore someone in need. Despite discarding his ideals, that did not change that particular aspect of his person.

"I just wished I could have saved someone… just as how I had been saved."

Shirou hesitated as his leg raised to take a step, determination warring with doubt as he struggled internally. Could he really just go back on all that he had done? Did he really have the right to shoulder that wish after what happened?

Shirou growled as he saw more men in identical black suits pour out from nearby streets. The girl was still holding her own, but the combined offensive by the men and the occasional explosive blasts from what seemed to be their leader were slowly but visibly eating away at her strength.

If he wanted to act, he had to do so soon, or it would be too late for the girl.

"All you need to do is hold on to that wish."

Shirou exhaled as his hands closed on imaginary hilts.

He did not have an answer.

He did not know if he could ever truly find it in himself to once more pursue the ideal he once kept. But at that moment, Emiya Shirou knew one truth.

One does not need to be a hero to reach out to another in need.

"Trace…"

Blue light flashed in his hands as a fire flickered to life in the eyes of Emiya Shirou.

"…On."

Author Notes

Hello readers, this is the first fanfic I've written on my own and the first I'm publishing anywhere. So I truly appreciate any comments, reviews and criticisms you might have as these will help me improve with time.

I follow both F/SN and RWBY in series and in fanfiction and I thought that the elements in each made for a rather interesting integration. That and I had inspiration and decided to start writing. I had noticed that several other fics had gone with UBW Shirou and I wanted to try for something slightly different. Not to say that their approach is bad (I have seen some good crossovers using that approach), but rather I don't want to stick to something that has already been tried before. As both an avid reader and a new writer, having variety is something I like to see.

This is… I guess you can call it a variant of Heaven's Feel Shirou. I like to see this as a possible Bad End where Shirou fails in everything but still manages to destroy the Grail in the end. For those who may not like the premise, I apologise but this was the idea I had.

This chapter is closer to that of a prologue than a true chapter 1, but I realised that splitting this into a proper prologue and a separate chapter would result in both being rather short, so I decided to put them together. As of now, I have the story planned out up to and including the Breach that happens at the end of RWBY season 2 and will continue working on how I envision the story to go. As the story moves along, there will expectedly be divergences from canon, starting with small changes that will later lead to larger ones. The butterfly effect if you will.

Thank you for reading this fic of mine and if you have questions, please leave a review or send a message. I will do my best to answer the more pressing questions in the following chapter's AN so long as they don't spoil any future details. I hope that you will enjoy reading this fic as much as I did writing it.