Chapter Text
Prismatic Shield Hero Rising
A Rising of the Shield Hero/Tate No Yuusha No Nariagari x Prisma Illya crossover.
Chapter 1 — The Fifth Circle
The sky fractures.
Not metaphorically—physically.
A vast magic circle spreads across the stone floor of Melromarc’s summoning chamber, layers of runes overlapping, rotating in opposite directions as magical energy floods the room. Court mages brace themselves, staffs pressed hard against the ground, voices raised in synchronized chant. The air vibrates, heavy and electric, as if reality itself is being pulled taut.
Four pillars of light descend.
Four figures materialized within the circles—each holding, bound to them, a weapon that does not exist anywhere else in the world.
A shield.
A sword.
A spear.
A bow.
The summoning succeeds.
The king exhales in relief.
And then—
A fifth pulse surges through the chamber.
The magic circle stutters.
Runes flicker. The flow of magical energy spikes violently, spiraling out of control for a heartbeat too long. One of the court mages shouts in alarm as a smaller, unfamiliar circle forms at the edge of the chamber—misaligned, imperfect.
Light erupts.
*Insert FGO Servant summoning animation*
When it fades, there is silence.
Five figures now stand where only four should be.
The fifth is small.
A girl—around 11 years of age—stands unsteadily at the edge of the summoning circle, silver white hair tied neatly, a simple hairpin holding it in place. She wears a summer school uniform: short-sleeved blouse, pleated skirt, socks slightly rumpled from the sudden displacement. Her hands clutch at her sleeves as she looks around, wide red eyes scanning the unfamiliar hall.
The mages freeze.
The king stiffens.
This was not supposed to happen.
Moments earlier—
Illya is on the roof of her school.
The afternoon sun is warm, the breeze gentle. Miyu stands close beside her, calm as always, while Kuro lounges against the railing, arms crossed, wearing her usual crooked grin.
They’re talking—about nothing important. Just enjoying their everyday lives.
Then the air pulls.
Illya feels it first. A tug, sharp and sudden, like invisible fingers wrapping around her chest. Her breath catches. The world distorts, colors stretching, sound warping into a dull roar.
“Miyu—!”
“Illya?!”
“Kuro—!”
Hands reach for her.
She sees their faces—shock, fear, panic—as she begins to fade. Kuro lunges forward, fingers brushing Illya’s wrist for a split second before slipping through light. Miyu calls her name, voice breaking, as the rooftop dissolves into blinding white.
Then—
Stone.
Noise.
Strangers.
Illya falls face first to the floor, groaning in light pain.
She then notices that she is not alone.
In the summoning chamber, the four heroes stare.
The one with the spear recovers first, eyes widening as he looks her over. “Whoa—wait. There’s a kid?”
The young man with the sword frowns, confusion tightening his expression.
The older boy with the bow gaze sharpens, cautious, analytical.
The shield-bearer says nothing, eyes flicking from the unfamiliar magic circle to the girl standing within it worries about the little girl and helping her stand up.
The king rises from his throne.
“What,” he says slowly, carefully, “is the meaning of this?”
No one answers.
Because no one knows.
Illya swallows. Her heart is beating fast—but she stands straight, forcing herself to breathe evenly. Ruby is there, quiet, reassuring, her presence hidden within as she has taken the form of a hairpin. She is not scared. Not really.
Just… lost and confused.
The king gestures sharply, regaining control. “Enough. The summoning is complete. Bring them to the audience chamber.”
His gaze lingers—just a moment too long—on the girl. And is washed by a tidal wave of emotions.
The audience chamber is vast, banners hanging from high stone pillars, sunlight filtering through stained glass. The four heroes stand before the throne, still strangers to one another, each unconsciously gripping their weapon. Both appreciating the decor and structure and just looking around in wonder.
Illya stands slightly apart.
She feels small.
The king surveys them, expression composed once more. “You are the heroes summoned to defend this world from the Waves of Calamity. Each of you bears a Legendary Weapon.”
He points.
“You, bearer of the spear.”
The spear hero straightens, a confident smile flashing across his face. “I’m—”
He stops himself deciding he needed to show his cool side, the little girl looked lost and he should at least project a reliable image.
“I am Motoyasu Kitamura,” he says instead with a cocky grin, bowing slightly, then glancing at Illya.
The king moves on. “You, bearer of the sword.”
The swordsman inclines his head. “Ren Amaki.”
“And you, bearer of the bow.”
“Itsuki Kawasumi,” the archer says calmly.
The king’s gaze slides to the shield-bearer.
“You,” he says flatly.
The shield hero opens his mouth—
“Enough,” the king interrupts dismissively. “You will receive your instructions later.”
The shield hero closes his mouth.
Illya notices.
She doesn’t understand why—but something about the way the king speaks to him feels… cold.
The king’s attention shifts.
Only now does he truly look at her.
The girl standing alone.
His expression changes there is a nearly imperceptible widening of his pupils...then… his facial expression.
It softens.
The king remembers how his young invalid sister looked, it was strikingly similar to this young girl…back when they were children.
He descends the steps of the throne slowly, carefully, until he stands before her. He lowers himself slightly, meeting her at eye level.
“What is your name, child?” he asks gently. For a split moment his voice felt like it was breaking.
The images of a trashed room and a lot of blood… his sister gone.
Rage and vengeance… it was all he could think of back then.
A genocide of a race…the hakkuko had to pay for this, the murder of his sister, the death of his first son.
All for the little sister he failed to protect.
Illya hesitates, then answers honestly, her eyes a bit of worry.
“I am Illyasviel von Einzbern, your majesty”
The name echoes.
Whispers ripple through the court. The structure of it, the weight of it—”von”. Nobles exchange glances. The air subtly tightens with imagined implications. Had they unintentionally summoned someone of nobility/royalty?
The king’s breath catches, not caring about such thoughts...
Something flickers behind his eyes—recognition without context, pain without explanation. He smiles, warm and kind, almost too kind.
“Ilyasviel,” he repeats softly as if commiting the name to memory to distinguish from something else… bit he couldn't, they looked so similar… painfully so.
Illya feels it then..
“I don’t know why, but… this king…”
Her chest aches, looking at the forlorn look on the king’s face…
“He feels like… he is sad…And in pain.”
Later, MUCH later, after the formalities end, after the heroes are escorted away, a message arrives.
A page comes to Ilya…
“The king requests Illya’s presence.” He said.
Alone.
Ilyasviel felt worried but from what she garnered the king seems to be an okay person… if all goes wrong she can rely on Ruby to blast him kingdom come.
In his private chambers, he bows to her.
“I, Aultcray Melromarc XXXII, the king of Melromarc have to apologize, in our attempt to summon heroes to save our world we have unwittingly called you by happenstance… this was a grave mistake, however we shall endeavor to make your stay pleasant as we try and figure out a way to send you back, however it might be difficult due to the calamity we are going through…” the king says as he explains about the waves of destruction to her.
His tone is kind and sweet, he looks truly remorseful… and in his eyes… a truly all encompassing pain that Illya can't help but feel.
Illya listens.
Nods.
She still doesn’t understand this world.
But she understands people.
And this king—
He is hurting.
And they spent some time conversing as the king began to ask her a bit of her world. The king was kind and brought drinks and sweets as he listened enraptured to the stories a young child was telling him.
“Compulsionary education, my word… while that would create problems due to using an apprenticeship method we lack people to work on clerical areas, as those are severely understaffed… but if commoners did receive and education, we could solve that problem, however there lies another problem, due to being an apprenticeship system, most jobs from the populace are handed down to family… however I also know sometimes children do not have the skill or drive for a certain profession, but do in others, I believe we could implement something that could bridge this” the king said, “a system of education where skills could be taught to any and all who would be willing to learn and could afford a small payment to be properly certificated, thus increasing quality of work AND workers”
Illya noticed that the king had taught of what essentially could be considered TRADE SCHOOLS.
Illya was amazed at the intelligence of this king.
And somewhere far away, beyond worlds and summoning circles, Miyu and Kuro are still reaching for her, unaware that a mistake meant for heroes had drawn a child into a war she was never meant to be a part of, not due to her being powerless, but because her presence would destabilize the whole world.
After that, she is escorted back to where the heroes have gathered. They have been given a room to unwind until they get private quarters to sleep… They all turned around to see Illya who arrived escorted by the people who worked at the castle.
She was a small child no older than 11, with unblemished white skin and white silver hair, her school summer uniform clinging to her figure. She gave an ethereal cuteness that just pulled at people's heartstrings. A perfect blend of innocence and cuteness.
“ Okay, I am gonna come and say it…” Motoyasu said with a small chuckle, “she is really cute.”
The others stared at him, a few raised their eyebrows.
“What?” he protests. “She is!”
Reluctantly, they nod.
Illya was blushing at the compliment.
“You are… Illyasviel, correct?” The one with the shield asked.
She nodded “yes, you are…?”
“Ah, right the king didn't let me introduce myself, the name is Naofumi Iwatani” he said.
“Nice to meet you Iwatani-san, but you can all call me Illya, is shorter” she smiled.
It was then they decided to chat a bit.
“Doesn't this remind you of a game?” Ren asked.
“Now that you mention it… yeah, I played that game a lot at home.” Motoyasu said.
“Yes, I am one of the stronger players in the game,” Itsuki said.
“Reminds me of Brave Star Online… I love that VRMMORPG”
The others looked at him in shock. “VRMMORPG? You mean like fulldive? Isn't that from like light novels and the like? No way also what's with the name I never heard of that game” Motoyasu said.
“Eh? But it's all the rage” Ren said defensively.
“You must be talking about Dimension Waves I played it a lot on my game system” Itsuki said
“Nonsense i never even heard of said title” Ren said.
“You must be talking about Emerald Online” Motoyasu said with a grin.
They all were about to butt heads when they turned and saw the young girl looking at them and then they kinda felt ashamed, as the older boys they felt they should at least give a good example to this child.
“Oh? ok what do we have here? Well I'll be, we've been summoned or rather Isekai-ed uh Ilya? But not the normal way it seems, truck-kun didn't deliver you this way uh?” A voice sounded inside Illya’s head, it was femmenine, familiar… and ANNOYING.
“Ruby?! Do you know how to get us out? Maybe doing a parallel world jump?! Like what we did to get to Miyu’s own world?” Illya said via their mental link.
Ruby looked smug… if hairpins could look smug, but her voice was filled with it so a mental image was not out of the question. “That is a good idea, however there-in lies the problem, this is not YOUR world, so no matter how many times we do it, we will only jump into parallel of THIS world, what we did to get to Miyu was to go from world A to world B, this would be world 1, so I am afraid that unless we have a multiversal navigation guiding spell we are stuck till they manage to find a way to send us back… or the issues the king told us are resolved… those… waves” Ruby said.
Illya inwardly sighed.
She then notices that the weight in her thigh was a bit more than before, THE CARD HOLDER!
She looked and pulled a rather fat deck of cards… which was odd as she distinctly remembered having only 8 class cards….
7 class cards plus the extra Gilgamesh card… (Kuro however was using the Archer class that held the possible future of her brother Shirou as the Counter Guardian EMIYA, which when she found that out, could not help but be shocked back then) she also saw that she had classes she never even HEARD of such as Ruler, Avanger, Beast, Shielder, Foreigner, Faker among others.
“What you got there?” Itsuki asked friendly, as he saw the deck of cards and saw the design. “Oh? A TCG?, those look nice design wise” he said.
Thankfully none of them knew what they really were.
“Illya, how dumb can you be? I mean I get that you are a dojiko/healing cute mascot type character but that was really dumb” Ruby said not even hiding her mirth from her voice.
“WHAT'S WITH THE VERBAL ABUSE?!” she inwardly screamed but Ruby wasn't listening to her.
Ruby decided to scan the weapons that the boys held in their hands. “Oh? What's this? This is interesting, those weapons are basically what you may call… modular noble phantasms in the making” Ruby said.
This startled Illya.
“They have a very structured system, since we are gonna be stuck in this world, which, by the looks of what I seen on these weapons holds true, is governed with laws of that of an RPG game so in a way, what the 3 boys were discussing was not really that far off” Ruby said.
Illya was doubtful “but that doesn't matter” Ruby continued, “because we are here, we are not constrained by the law of secrecy we have in our world regarding mystery (magecraft) meaning we can become the ULTIMATE MAGICAL GIRL!!”
Illya felt like banging her head on the table… of all the stupid…
Ruby, however, was also thinking of keeping her safe. So she decided to stea- borrow the system that the Cardinal weapons function and none of their restrictions… as well as getting the status magic system, this way Illya may be able to grow and be able to protect herself and have a better safety net… AND WORK TOWARDS BEING THE MOST POWERFUL MAGICAL GIRL AND LEAVE THAT BARDICHE IN THE DUST! TAKE THAT NANOHA!
Illya and somewhere in the many worlds Nanoha felt a slight shiver.
The guys decided to check for something as what they said did not align with their own knowledge.
“Ok then, let’s start with some common-sense questions. You can all name the current prime minister, right?”
“Sure.”
“Ok, let’s all say it at the same time.”
Gulp.
Obviously Illya wouldn't be participating on this as she is much too young to know or care about such things.
“Masato Yuda.”
“Gotaro Yawahara”
“Enichi Kodaka.”
“Shigeno Ichifuji.”
They all fell silent. Illya was aware of what it meant, even Ruby herself shook a bit.
The summoning of them used aspects of the Kaleidoscope!
Then they went on to compare their knowledge of Internet terms, famous Internet sites, and famous games. None of their examples matched up. In the end, they didn’t seem to share any references at all. Their worlds,while being the same, had many differences.
“It kind of seems like we all came from different Japans.”
“It does seem that way. I certainly can’t imagine how we could be from the same place.”
“I guess that means that there is a Japan in all our parallel worlds?”
“I thought at first that we could just be from different time periods. But none of our experiences match up, so that can’t be it.”
Even at that, they all had one thing in common: they were Otaku. That had to mean something.
“If that’s the case, it seems like we were all brought here for different reasons, and in different ways.”
“I’m not really into having useless conversations. Do we really need to have these things in common anyway?”
Ren spoke up as if he was the coolest person in the room, and he wanted everyone to know it.
“I was on my way home from school when I hit a spot of bad luck and got caught up in a murder case. It was the talk of the town at the time.”
“Uh huh.” they said as if asking him to proceed.
“I was with a good friend. I remember saving him, and I remember the criminal getting arrested…”
…Ren was rubbing his side, softly, as he spoke.
Illya was impressed, however she felt sad and gave a pained expression at learning that he caught the bad guy but then was stabbed in the side during the struggle to save his friend.
Naofumi felt the guy might not been telling the whole story, or maybe even embellishing it, however he was summoned as a hero. “The least I could do was hear him out.” he thought to himself.
“Anyway, so then, before I knew it, I woke up here.” Ren finished.
“Makes sense. Pretty cool of you though, isn’t it? Saving your best friend and all?” Naofumi said.
He responded to his compliment with even more aloofness.
“Ok, I guess I’m next,” said Motoyasu, lightly pointing at himself.
“I have… Well, to put it simply… I have quite a few girlfriends.”
“I’m sure you do.” Naofumi said flatly.
Illya’s fave changed a bit but it held a clear look of contempt and askewance.
“And well…”
“You had too many at once, and they stabbed you or something?” Ren said, laughing to himself.
Motoyasu snapped his eyes open in surprise then nodded.
“Yeah well… Women are terrifying.”
“Gigolo” Illya said.
Motoyasu looked like he got stuck by an arrow.
“I bet you were playing with their hearts, and when they found out THAT happened… let me guess, both where the yandere type uh?” She said as each word said by her was a psychic damage to his ego, the other 3 were shivering in attempts to reign in their laughter at seeing a little girl dressing down Motoyasu for being a playboy, until it got so bad they started to cry-laugh, making Motoyasu blush and feel even worse. Naofumi felt indignation at the story of how Motoyasu got here. He literally caused his own demise for being frivolous, so the little girl… Illya, he reminded himself, dressing him down was not only deserved but ironically delicious.
But wait… Itsuki placed his hand over his heart and began to speak.
“Now it’s my turn. I was on my way home from prep school. I went to cross the road, but a dump truck came screaming around the corner at full speed. And then…”
Again, we all fell to silence.
So he was almost certainly hit by a truck… What a sad way to go…
That was… the most trope-like way to be isekai-ed, no?
Illya hissed a bit, due to Ruby’s previous joke comment. It now felt in bad taste.
Naofumi then blinked… as his way of coming here did not involve him dying… if anything he was the only outlier, at least so far.
Then a dark and morbid thought surfaced… “Could the little girl, Illya, have also been struck down? At such a young age?!” Naofumi thought with worry
“Uh… do we really all have to talk about how we got here?” he said feeling uncomfortable, not for himself but for the others…
“Well, we all already have.” Itsuki said.
“I guess. Well… Sorry, everyone. I was at the library, flipping through a book I’d never seen before. Before I knew it, I woke up here.” he said earnestly.
Again, silence.
They were staring at me, cold as ice.
Naofumi was taken back, why are they acting like that?
Then the 3 looked at the young girl, she felt self-conscious due to the attention she was getting.
“Guys, don't pressure her, just let her be, she is a child so…” Naofumi said in defence of Illya who felt appreciative towards his actions. She shook her head.
“Thank you Naofumi-san, but I understand, they are also worried, and wanted to see if they could have common ground… my coming here didn't involve anything like that, it was like Naofumi, however I was in the roof of my school eating lunch with my… cousin Kuro and my friend Miyu when suddenly I felt a compulsion and felt something grabbing me, they both were shouting and jumped to grab me, however by then it was too late… and found myself face first with the stone floor.” she said nursing a phantom pain.
Illya looked miserable, Naofumi glared at the other 3 who looked rather ashamed at making her look so sad, so they decided to change the conversation so as to not linger on this topic.
The three of them started whispering among themselves so that I couldn’t hear what they were saying.
“Yeah… but he… he has a Shield.” Motoyasu said.
“I knew it… Motoyasu, you too?” Naofumi said.
“Yeah…” Motoyasu said with a pained grin.
“All right, so is it fair to assume that we all have a pretty good idea about how the system in this world works?” Naofumi asked
“Sure.”
“Done it a thousand times.”
“I think I get it well enough.”
Naofumi realized that he and possibly Illya were the only ones without a foundational knowledge of how this world operates!
“W…Well…. Maybe you guys could teach me what I need to know to fight in this world? There were no games like this where I’m from.” he said, hoping to get help and also for Illya’s sake.
Ren narrowed his eyes and glared at Naofumi. Again, ice-cold. For whatever reason, Motoyasu and Itsuki were looking at me with kindness.
“All right then, your big brother Motoyasu will, as best he can, teach you the basics.” He sounded fake, with that big smile on his face. Soon his hand was on Naofumi’s shoulder, and he was talking away.
“First of all, and I’m only talking about the game I know, Emerald Online… but you’re a ‘Shielder.’ Basically, your job is to use the Shield and protect people.”
“Uh huh.” that seemed par per course and obvious.
“In the beginning, your defense is super high, which is great and all, but as you go up in levels, the damage you start to take gets a little unbalanced.”
“Uh huh…” he did not like where this was going.
“There are no high-level Shielders. At higher levels, it’s a rather useless class.”
“Noooooooooooooo!” He felt despair, his “character class” was just gimmicky?!
“What about updates? Were there no updates?” Naofumi asked.
Like… to balance out his class?!
“Nope. Because of the game’s system, and because of the game’s population, the class was abandoned pretty early on. It’s really not good for much. I think they had even planned to delete the class altogether…” Motoyasu' said with a pained smile
“And I guess I can’t change jobs?!”
“Well the associated jobs are all… how to put it? Dead.”
“And I can’t change?” Naofumi asked.
“Nah, the game never lets you switch to another job tree.”
Wow, so he was stuck with a useless class?
“What do you guys think?” I asked, turning to Ren and Itsuki, but they both turned away from me.
“Sorry…”
“I feel the same…”
“What about the geography of the land?” Naofumi asked.
“The names are different, but the map seems to be the same. If the map is the same, there’s a high probability that the division of efficient monsters is the same also.” Ren said.
“The best hunting grounds will be different for each weapon. Probably best to make sure we go to different places.” Itsuki said.
“True. We need to focus on efficiency.” Ren said, nodding his head sagely.
Naofumi thought that since he couldn't do much on his own then the others would at least help him by carrying him a bit till he was able to figure things out…right? That’s how it was supposed to work, right?
Naofumi thought it would have been great if he could get a pretty girl in his party… in his world he never was able to meet a cute girl, but things might be different here, or at least he hoped.
“Hmm… Well, it will be fine. I mean, we are in a whole new world! Even if I’m not the strongest character, I’m sure something will work out.”
They looked at him as if they were looking at something pitiful… or at least, that's how Naofumi thought that’s how they were looking at him. Besides, he was equipped to defend, and this wasn’t a game. I could just get rid of his special shield and get a weapon instead…
“All right, let’s do this!” I forced myself to show some gumption.
“Heroes, we have prepared a meal for you.”
What’s that? Looks like we were going to get a nice dinner.
“Nice.” they all said.
After eating a special feast prepared for them they went to their prepared rooms, Illya had a room that she noticed had been cleaned recently and thoroughly… Ruby, still posing as a hairclip, scanned the room for any signs of magical eavesdropping, after that she used one of her 208 secret devices, which created an eavesdropping proof field.
She then flew from Illya's hair and took her round form with wings.
“yaaaaaa!!! I felt my muscles stiff from playing the role of a hairclip” Ruby said.
Illya just deadpanned, “But… you don't have muscles”
Ruby, with her wings, then grabbed her cheeks and stretched them out.
“Ouch ouch ouch!!” She yelled out in pain.
“Uuuf… that's a good stress relief” Ruby said as she wiped (non-existent) sweat off her (non-existent) brow.
“Don't use me for stress relief like that!!”
“So, it seems this ritual to summon heroes is loosely, and I have to use the word loosely here VERY loosely, ironic I know… in the ritual similar to servant summoning from an alternate reality of yours… it uses some concepts that border on the second Grand magic, the kaleidoscope… the fact that we can't sense our maker here means that they only managed to cobble it up but made it works which shouldn't be possible, but since there is no Gaia or Alaya, it might been possible to just brute force it?” She said, but not really believing her own explanation.
To Illya this might as well be astrophysics in Swahili…
But she got the basics.
“So, because it was kaleidoscope… you were somehow dragged in? And, I assume, but probably more certain than anything, you dragged me along?” Ilya said.
This time Ruby was serious. “I may like to tor- I mean tease you from time to time-”
“YOU WERE GOING TO SAY TORTURE WEREN'T YOU?!” Illya yelled as she shook Ruby.
“But even I wouldn't drag you to something this big, the Class cards, I knew the risks, and I knew you had the ability to gather them, which is why I decided on you, which also served to piss that hag” Ruby said, by hag referring to Tohsaka Rin.
Okay… so Ruby, for once, was innocent… Illya wondered if the world was ending.
“Oh right… the waves” she thought of the talk with the king.
“Anyways, while you where with your reverse harem” Ruby said making Illya flush beet red as she tried to strike at Ruby, who just floated high enough to be out of reach, “I analyzed the system those weapons run in… apparently they are not unlike me, except I am more powerful and top tier and have no pesky rules to follow” she said feeling proud of being a delinquent.
“Because it has a similar system, SIMILAR, not the same… I copied everything they had to give you the same… should we say “admin rights” they have? Except yours would be different… they are bound to their weapons and have many demerits, like, they can't Collab, if they fight near each other they get 0 EXP, what the heck is that?! Not to mention the demerit of even TRYING to use any other weapon other than the weapon they got bound to? Unable to enter other realities without permission from a holy beast? Having someone with an ability to mitigate any hero attacks? Noooo thanks, we're gonna go rogue here!” Ruby said with cheer, cheating the system is a classic Ruby move.
“But what about… this?” Illya said as she unloaded the deck of servant class cards.
“Now that… I don't know, maybe this is all part of a fanfiction writer who is trying to be ambitious and have so many new forms and abilities to transform, and by doing so you might change the original setting of the series that this is grounded in?” Ruby said.
Illya just stared at her flatly, too emotionally tired to really care.
She crawled to the bed, which was so soft she could feel she was melting INTO it and fell asleep.
Ruby, due to not needing sleep, decided to keep guard.
Chapter end.