Disclaimer: I do not own Fate/Stay Night or My Hero Academia

...

To say that there was some manner of confusion going on was an understatement as students from every school found themselves in a world unlike anything they had ever seen before. The few professional heroes that had been fighting off the vast numbers of villains in the stands braced themselves for whatever quirk had manifested this world around them.

It mattered not to Shirou as he now had visual access to each and every person who was in the Unlimited Blade Works. That also included those who had been injured and even those that had died during the explosions that had gone off earlier. Lives of children that had gone to waste.

The villains that had been surrounding him questioned themselves and those around him about what had just happened. Thousands of clones made the all too fatal mistake of pausing in the heat of battle. A mistake which Shirou wasted no time in exploiting.

The students and heroes who had stopped looking at the world around them and had focused on the sheer number of enemies braced themselves for the next stage of the fight. What none of them could have expected however was the absolute masacre that came next.

In a single second, steel rained from the sky bringing with it limitless death. Before the clones could even contemplate what was happening they found their bodies pierced by swords of all shapes and sizes, ending their existence without question. As some tried to create more copies of themselves before their time came to an end, it mattered not as fresh steel plummeted into the new clone before it could fully be formed.

An invading force which had pushed the students present to their absolute limit, wiped out in an instant. "What, the actual, fuck," cursed Bakugo, unable to comprehend what it was he had just witnessed.

"This is...Shirou's ultimate move?" questioned Yaoyorozu, taking the time to bear witness to the world around her.

It was during this period that the students began to merge together, still in shock and awe at the situation they found themselves in. There was also a range of questions springing forth from those who had some very obvious questions.

"Where the hell are we?"

"How should I know?"

"Is anybody freaked out by the fact there are swords literally everywhere?"

Kirishima plucked one of the swords out of the ground, holding it in the air for his schoolmates to see. "Does anybody else remember the bus trip to the training with Thirteen?" he asked of those around him.

"I remember more about the villain attack that happened," said Aoyama.

"Kinda," said Jiro. "What about it?"

"Well, Shirou said that he could only create weapons that he's seen before," said Kirishima as he lowered the blade slightly before gazing well beyond the people standing around him. His following question didn't even need to be asked as those who had heard him speak knew exactly what it was that was on his mind.

Elsewhere among the endless wasteland, Spinner looked on in awe at what was around him. Had the League of Villains known that one of these students had a quirk that could rewrite the very landscape around them? Had the real reason the main members of the League hadn't been there and had been attacking another target was because they knew if they came here the chances of them being killed was high? Were they sent to die to confirm that this person was willing to act in a villainous way in order to save others?

There were far too many questions circulating at the moment and none of them had a positive error.

A bestial roar echoed from the distance, making Spinner flinch at what he heard off in the distance before he saw something launching in his general direction. He didn't have to move as said item crashed into the ground near where he was standing. Unfortunately he was close enough to see exactly what it was, or more importantly who it was.

Considering he had been standing with that person mere minutes ago, he felt that he would easily recognize their disembodied torso.

...

Shirou stood at alert bracing himself for anything that may be within his realm. He could see the students assisting one another, helping those who were wounded and mourning friends who had died.

"Shirou..."

The magus turned at the sound of his name, Midoriya standing behind him having walked through whatever remained of the clones that had been slaughtered. The green haired teenager had a few scrapes and bruises on his face showing that he had been caught up in the conflict somewhere. "What is it?" he asked calmly.

"Just...what is this place?" asked Midoriya.

Shirou pondered briefly and wondered how best to describe it. "This is my presence being forced onto the world, everything in here is mine to command."

"If you could have done this...why didn't you do it earlier?" asked Midoriya before a terrifying bellow echoed over the field, forcing many to cover their ears at the sheer volume of it.

"Because of that," declared Shirou.

...

Aizawa was a professional, very few could even contemplate denying that fact. During the scuffle before he had been utilizing his quirk to the fullest in order to try and slow down the swarm of clones threatening to overrun the arena floor. He had known just how best to utilize his quirk and had made sure to do just that. Many of the students likely would never know about how he had contributed and he wasn't one to make mention of it.

Now however, he had a feeling that he very much would be required to do something a little more out of his comfort zone. He was used to being able to tackle enemies far larger and stronger than himself, all of those who were unaffected by his own quirk.

This however was a situation where he was completely out of his depth in what looked like a world comprised out of somebody's knightmare. "Eraser...what happened?" asked Ms Joke, the teacher from Ketsubutsu Academy seemingly unable to comprehend what was going on.

"My student seems to have been holding back on us," commented Aizawa as his gaze lingered over the innumerable amount of blades surrounding everyone he could see.

"Your student? You mean the one that wasn't participating? He could do this!" exclaimed Ms Joke. "Why wasn't he down there competing? This kind of quirk could..."

"Could be a complete drain on his body," stated Aizawa, completely derailing his fellow teachers train of thought. Aizawa knew that Shirou's power didn't work the same way that the rest of the society was and for as much of a fight he had put up against All Might when the two had collided he hadn't utilized this technique. He imagined that was because his body couldn't maintain the shift for a long period of time or by having done this the rest of his skills would be dulled. There were dozens of theories he could craft together but none of that mattered right now.

What mattered was that Shirou had saved the lives of hundreds in the span of seconds and done more than what anybody else could have. There was still a lingering threat however though. None of the students or those who had been employed to help in the exams had made themselves known. If they began to think that this was another technique from a villain as opposed to a student, panic could undoubtedly set in and accidents could most definitely happen in these situations.

He believed that Shirou knew this and if this was constantly draining his strength, why hadn't he dropped whatever this technique was? The only reason he could think of was that Shirou believed the threat wasn't over. If that was the case, what was more threatening out here than the swarm of villains that he had just taken out?

The answer became immediately obvious.

The bellow that rang out sent both the professional heroes on high alert, turning towards where the monstrous sound had come from. From the distance they could hear the sound of footsteps barreling ever closer. Given that the person charging towards them was still a fair distance away, it made it more than a little terrifying that they could hear them from so far away.

"Brace yourselves," declared a new voice, Ms Joke looking over her shoulder to see Gang Orca standing there whilst Aizawa kept his gaze focused on the incoming threat.

"Gang Orca," said Ms Joke softly, looking up at the number ten hero. Unfortunately it looked as if the top tier hero had taken some injuries during his confrontation with the villains in the stadium. It was also quite obvious that he was alone. "Where's your..." Ms Joke didn't have the stomach to finish her question.

"Dead," confirmed Gang Orca, knowing full well what Ms Joke had been unable to ask. "Beaten and bludgeoned to death. I will mourn for them once the threat has passed but for now we must focus on the battle at hand."

"Here he comes," stated Aizawa as he readied himself. Gang Orca did the same but Ms Joke however found herself losing face a bit. She was known as being the most cheerful one in the world, going out of her way to make anybody around her burst into laughter. Everything that had happened however, it was difficult to even bring the smallest of smiles to her lips.

"There is no shame in avoiding this fight," declared Gang Orca. Were Ms Joke to be in her right frame of mind she may have been insulted by the comment. "There were people from the Help Us Company who were meant to be utilized in the second part of the exam. Find them and keep them safe."

He may not have said it but Ms Joke knew the underlying meaning of his words. The calibre of enemy coming at them ensured that he had to go all out and there may be no way to keep her safe once the fighting began. "Got it," she said, trying to keep some manner of face as she turned on the spot and ran off into the desolate wasteland. At least her quirk could hopefully be used to prevent the civilians from doing something rash.

For Gang Orca and Aizawa, their enemy had just come into sight and Eraserhead suddenly found a pit drop within his stomach. For he had seen this enemy before take an explosion head on and not even flinch, clash with an opponent at speeds that were difficult to track and even stitch himself together after having nearly been cleaved in half.

What had Shirou called him again?

Oh, that's right.

Berserker.

...

Midoriya blasted across the wasteland, shouting a warning at the top of his lungs. It was a simple message really and everybody who heard it did heed his warning.

It was fairly simple really. After an invasion from villains attacking students, someone shouting that everyone had to run for their lives seemed more than willing to listen. Those who heeded the warning made their way in the direction Midoriya was pointing, the opposite way to where the confrontation was likely to be.

"Midoriya!" shouted Iida, the speed quirk user bolting up to where Midoriya was currently doing his best to control traffic. "What's the meaning of this? Shouldn't all those still able to fight be heading to where this villain is?"

"Because if we go over there, Shirou can't go all out," explained Midoriya.

It took all of four seconds before Iida was mimicking Midoriya's actions, albeit in a more robotic action, as he knew that the safest place to be for everyone, wounded or not, was as far away from the conflict as possible.

...

Ochaco ran in the direction the rest of the crowd was going, Toga upon her back weighing nothing due to the use of her quirk. All of that extra training she had been forcing herself through was paying off because, as far as she was aware, nowhere was a place that would be declared as safe.

"Can't we watch the fighting?" asked Toga, seductively whispering in her ear.

"No," replied Ochaco without a second of hesitation.

"Why not?" whinged Toga, disappointed with the answer she had been given.

"Because I really, really enjoy not being dead."

There was several seconds of silence between the two of them as they continued moving to safety. "You know, all that does is make me want to watch it more," stated Toga.

"And we're still going as far away from it as possible!"

...

Spinner had, for all intents and purposes, started absolutely legging it as soon as the bloodied torso had landed near him. Of course there had been a brief period where he had been frozen in shock at the sight of the disembodied villain and the organs spilling out of him.

Straight away he realized that this wasn't the action of a hero, which only meant that there was a villain far more terrifying than the criminal that he was. Hence he had ran.

On hands and knees, Spinner did his best to take in as much air as he could. Sure his mutation quirk gave him extra speed and stamina but that didn't necessarily mean that he was used to running as fast as he could for as long as he could without pause.

"Are you in need of assistance sir!"

Spinner turned his head to look at the student standing by his side and watched in shock as the teenager bent over at a near impossible angle and crashed his head into the ground.

"I am so sorry if me asking if you needed help has offended you sir!"

Spinner stared blankly at the man for a while before relaxing somewhat. If he was going to get rescued he might as well be rescued by the weirdest one of the bunch.

...

There was no denying that Gang Orca was a powerful hero. One didn't make it into the top ten without some manner of skill and popularity pushing them forward. Now though, his popularity didn't matter in the slightest as he used his voice in an attempt to paralyze the behemoth before him.

While it did make him stumble ever so slightly, the man growled it off before swinging at him with the crude club at his disposal. Gang Orca managed to dodge it by the barest of margins before launching a vicious right hand forward and striking at the man. Even though he had put every bit of effort he had behind it, it meant nothing as his fist struck the man in the chest.

If his hand hurt more than the man's chest, he wouldn't be surprised.

Eraserhead meanwhile was circling the battle between the two powerful warriors. While his quirk was useless in this situation, there was something else that he had at his disposal. All of the weapons that Shirou had seen throughout his lifetime.

Over and over again he picked up sword after sword, each a different shape and size before closing in and launching them at Berserker as hard as he could. The blades bounced off the brute without so much as making him look in his direction but that didn't stop Aizawa. He had been there when Shirou had spoken of his arsenal, how some of his weapons were crafted by the greatest swordsmiths to have ever walked the Earth. While these mundane blades did nothing against him, if he could stumble across a far stronger weapon, then maybe they'd have a chance.

Or he could be completely mistaken as Berserker grabbed hold of Gang Orca's arm and swung the professional hero over his head and crashed him into the ground with enough force to send weapons flying in all directions. Aizawa could do nothing as Berserker raised his weapon high into the air and prepared to deal a finishing blow before pausing.

With a bestial snarl Berserker leapt from his position mere moments before Shirou drove Rule Breaker into the space he had been standing. Gang Orca pushed himself up in a mild state of disbelief. The man he had been fighting had been able to go toe to toe with him and had him on the back ropes, prepared to kill him but the moment a student appeared he had gone on the defensive.

"He knows," muttered Shirou under his breath.

"He knows what?" asked Aizawa, running towards them knowing full well that Shirou had far more experience dealing with these enemies than he did.

"When I stab him with this," said Shirou, lifting up the dagger, "The possession ends."

"Is there any other way to stop him?" asked Gang Orca, not entirely sure what was going on.

"We can kill him twelve times," stated Shirou as the swords that were surrounding them burst into life and shot towards Berserker at lightning speed. The Heroic Spirit reacted by swinging his weapon into and out of the ground, sending large chunks of stone in front of him, many of which collided with the swords which had threatened to plunge into his body.

While many were deflected, some managed to sneak through and stab into torso. None of them however had managed to penetrate deep enough to do any sort of real damage and Shirou knew it. "Twelve times you say," repeated Aizawa.

"Kill him once and I can stab him with this, there's a brief period between each time he dies for his resurrection to kick in," stated Shirou as Berserker roared at them, clearly not wishing to wait a moment longer. Berserker leapt forward at a blistering speed towards the three of them, Shirou immediately swapping his weapon knowing full well that he couldn't match him with Caster's weapon.

As Kanshou and Bakuya blocked the strike which had threatened to cleave him in half it still pushed Shirou backwards he couldn't help the small smile that crept onto his face. Unlimited Blade Works was his realm.

It was time for a third rate Magus to take down a Demi God.

...

Hope you enjoyed.