Chapter 1: I Am the Bone of My Sword
My name is Emiya Shirou, 17 years old.
I am a transmigrator.
Here is how it happened.
Based on the intelligence he has gathered so far— Whether it be from the memories of his past life that have resurfaced, Or from the reflection in the mirror at home, showing a handsome red-haired youth, And the brown school uniform he is currently wearing, As well as the student ID he pulled from his pocket, which bears a photo of his likeness and the four large characters for [Emiya Shirou], alongside the label for Private Homurahara Academy— All of it proves without a doubt: he is indeed Emiya Shirou! The protagonist of a certain series from his past life's memories!
But the problem now is...
"Officer, if I say I have amnesia, would you believe me?"
"Do you think I'd believe that?"
"I suppose you should."
"Believe my foot!"
The Japanese male police officer sitting in front of Emiya Shirou slapped the table in anger.
"This place isn't some hostel!
What you and that other high school boy did was, at most, excessive defense. A verbal reprimand is enough; we don't need you sitting in jail wasting taxpayers' money!
So, if you understand, hurry up and give me your guardian's contact number and go home! How many times do I have to say this before you get it!?"
Well, that was exactly where the problem lay. According to the memories of his past life, at his current age, he should be preparing for the Fifth Holy Grail War. But in reality, by the time Emiya Shirou's consciousness came to, he was already detained at a police station.
Furthermore, because his identification documents seemed to be "incorrect," they couldn't contact his guardian.
He was being subjected to continuous interrogation by the police...
'Anyway, first, stay calm and count prime numbers.'
Subconsciously recalling this meme to soothe his nervous heart, Shirou suddenly realized a very serious problem—
'Prime numbers... what were they again? Do they start from 0?'
With the memories of his two selves constantly merging, causing some trivial memories to become blurred, Emiya Shirou fell into deep thought.
This distracted appearance infuriated the male officer, who had interrogated him countless times without managed to extract any real family information.
"Seriously, another problem student!"
After a muffled curse, the officer realized he was out of options and could only send Shirou back to the detention cell. After all, as mentioned before, Shirou wasn't a serious criminal—just a high schooler caught for excessive defense.
He couldn't exactly use a "Great Memory Restoration Technique" on him.
Moreover, according to the description provided by Shirou's "accomplice," Shirou seemed to be the one who was just caught up in it. Of course, the officer didn't quite believe the other person's testimony.
They were dealing with four punks armed with clubs and knives. Even if Shirou and his friend were martial arts masters, there is a "high wall" between being unarmed and being armed; it should have been impossible for one person to beat those four punks so badly they had to be hospitalized.
However, since the other person had taken all the blame and Shirou wasn't talking, they didn't seem to have any other choice. Even though it wasn't a major case, it left a lingering sense of inexplicable frustration. ...At least, that was what the officer thought.
As for Emiya Shirou's thoughts? —
"Ho—! ...Holy crap!!" —"Holy crap! Holy crap! Holy crap! Holy crap! Holy crap! Holy crap!!!"
Forgive Shirou for having only this phrase in his mind; he truly couldn't find any other way to express himself.
Why would he, having just awakened his past life's memories, suddenly appear in a detention cell? Why couldn't he find any clues as to why he was here, no matter how much he searched his previous memories? Why did the police still not know his home address even after finding his student ID?
It turns out it wasn't him who had the problem.
It was the world that had the problem!
Seeing the iconic school uniform with the large gold chain, Shirou understood.
This wasn't the world of Fate/stay night or any other Type-Moon spin-off.
This was a world where even the author had changed—it was the world of JoJo's Bizarre Adventure!
That's right! The problem student locked up with Shirou, whom the officer misunderstood to be his accomplice, was none other than the protagonist of JoJo Part 3— Kujo Jotaro!
—[Ding—] —[Infinite Game System loading complete.]
What was going on? Before Shirou could figure out why he had crossed over from the Fate/stay night world to the JoJo's Bizarre Adventure world, a mechanical, cold voice suddenly rang out in his mind.
—[Detected that the Host was in a life-threatening state before the system finished loading.]
—[Based on the law of not standing idly by while the Host is in danger, the system will choose to unlock early for the Host's protection...]
Following this, a stream of information began to flood his brain. It allowed Shirou to finally understand what was happening.
Simply put, just like most Emiya Shirous in the Type-Moon worlds, he was supposed to have his heart pierced by Lancer before the Fifth Holy Grail War began. Shirou was no exception. And this time, he wasn't lucky enough to last until Tohsaka Rin arrived.
As a result, his past life's memories awakened due to the fatal wound. The system that crossed over with him began to unlock a portion of its functions early to protect its Host, causing him to travel to the world of JoJo's Bizarre Adventure.
—"Because your name is the 'Infinite Game System,' I've only traveled to this world with my consciousness, so I'm not affected by the injury of a destroyed heart?"
—[Yes.]
—"Because I was on the verge of death before crossing over, once the 'Game' ends and I have to return from this game world, I will die from the heart-piercing wound?"
—[Correct.]
—"And since this is just a game, whatever I do in this world won't affect my original body? Conversely, does that mean no matter what I obtain in this world, I can't save my original body in reality?"
—[Basically correct.]
After conversing with this sudden system in his head and repeatedly confirming his situation, Emiya Shirou remained silent for a long time before he couldn't help but complain:
—"Then what use do you have, System?!"
—[Please explore on your own, Host.]