Fate/Stay Night: Unlimited Boob Works

A fan fiction by Ammaranth

"Illya . . . are you sure you want to do this?"

"It's okay big brother, I trust you."

Shiro Emiya took a deep breath, then spoke the words that had come to define his existence.

"Trace on . . ."

Rin slid the door closed behind her, then turned to the waiting Shiro and Saber.

"She's dying."

"How can you just say it like that!?"

"It isn't as though I don't care! An Einzbern homunculus isn't meant to last more than a few years. It's a wonder she's been able to live this long. Illya's half human, but she's still also half homunculus. And the homunculus part of her is coming to an end."

". . ."

"Look, Shiro – you've already done so much for her. You took her in, and made sure her last days have been happy ones – probably the happiest ones in her life. I can't imagine what it must have been like to grow up in the Einzbern Castle . . ."

Rin's voice trailed off as she glanced out past the verandah to the openness of the courtyard beyond, reflecting on what it was like to grow up as a mage in the Tohsaka family, and the secret envy she nursed for Shiro's own upbringing.

"You've already done more than most people would."

"Especially for a former enemy", Saber added gently.

". . ."

Rin squinted at him.

"Uh – oh, I know that look –"

". . ."

"It's that look you get when you're about to do something stupid –"

"I can't accept it."

"You don't have a choice!"

"I won't accept it!"

"And why not! Why can't you ever just accept that you're a good person, that you've done all you can, and that's all – why can't that be the end of it!?"

"I can't accept Illya dying!"

"You are so stubborn!"

"Big brother . . ." Illya called faintly from the other room.

"Oh fine!" Rin hissed in a shouted whisper. "Be that way!"

And so it was that Shiro and Illya found themselves sitting in the living room of the Emiya house. They had taken two chairs and arranged them together so that Illya sat facing the back of one, while Shiro sat behind her with his arms around her waist. Even though her body was cold, her skin was surprisingly warm to the touch. She had originally offered to take off her shirt, but he had assured her that wasn't necessary.

"If you say so, big brother."

In spite of Illya's words, the two of them were not actually related by blood. It had never been any secret that Shiro was adopted. His father had taken him in when he was ten years old, after his parents died in the disaster that he would later learn was the aftermath of the Fourth Holy Grail War.

He was a very open man, Kiritsugu Emiya, even about things that others would usually keep secret, such as being a mage – and he had showed what Rin considered a shocking disregard for his son's lack of progress in his magical studies. But he'd never said anything about having a daughter. Shiro hadn't found that out until the Fifth Holy Grail War had begun.

"The way I see it, Father couldn't wait for me, so he left you behind to take his place," Illya had said very matter of factly. "So that just means you'll have to take care of me forever."

And so Illya called him big brother, which Shiro did not like, which she was quick to pick up on, and so used the words at every available opportunity – especially in public.

"Don't worry big brother, what's the worst that could happen? If you mess up, I'll die – but then again, I'm going to die anyway."

With this doubtful assurance, Shiro uttered the words,

"Trace on –"

At once he felt a series of green lines fan out through his entire existence. They were the pathways of his magic circuit.

"Mage families spend a tremendous amount of time developing and guarding their lineage", Rin had explained, "All so that they can pass on their crest and magic circuits to the next generation."

It seemed a strangely practical way to describe something so arcane and mysterious, but to Shiro, who was used to fixing things like heaters and other household appliances, it made perfect sense. Illya, however, was much more complicated than a toaster.

"Tracing basic structure –"

The pathways of Illya's magic circuits opened up before him like a maze.

"That girl isn't so much a person with a series of magic circuits as a group of magic circuits with a little bit of a person around them", Rin had said.

Her description was true.

Shiro, as a novice, had his magic circuits mostly concentrated in one arm, while Rin's, as a trained disciple of one of the great mage families, were peppered throughout both of her arms and legs. But Illya's ran throughout her entire body.

The arrangement wasn't natural. Being half homunculus, the Einzbern family had felt no hesitation about tinkering with her design. From an early age, she'd had additional circuits from various donors grafted in to augment her own already considerable abilities – all for the sake of winning the Holy Grail War.

The process had been excruciating, but the dividends it paid in terms of sheer magical power were enormous. And for their present purpose, it had other benefits. The pathways of Illya's circuits were large, and easy to follow. The only problem was that there were so many of them he had to be careful he didn't get lost.

"Tracing component materials –"

He traced her skin, so pale and white, then moved deeper, into the connective tissues, marveling at the way that a single strand from her face carried on in an unbroken line, down her neck, past her shoulders, and throughout her body, all the way to the tips of her toes.

"That tickles –"

From here he moved on to her muscles – how small they were – and totally devoid of any tension.

"How can she relax at a time like this?"

Such was the peace of mind of one who had spent her entire life preparing for the Holy Grail War.

He felt the places where her muscles attached to her bones, which he found to be very thin and delicate, then changed over to listen to her breathing. He could feel the air rushing into her lungs, mingling with her blood before it travelled out, following the path of her arteries, then back again through her veins like a wave, all the way to her beating heart.

For a moment it seemed to pulse between his hands, her life passing through them with each beat.

Illya snuggled down and pressed her back against him.

He traced the course of her nerves, out to where they tingled in the tips of her fingers, then up, into her brain, where he felt the gaps between their synapses, whose chemical crossings made up the junctures in the pathways of her mind.

With a start he realized he could see her thoughts.

At the moment she was remembering a scene from when she was a much younger girl, playing with their father Kiritsugu in the snow.

"I'm sorry, Illya. I didn't mean to –"

"It's okay. I don't mind."

She answered him without speaking, and he realized she could hear him, and that maybe she could see his thoughts, too.

"I guess it's only fair . . ."

So many systems.

He made a quick search of some of the less savory ones. He could feel her digesting – evidently that pastry from the takoyaki stand had given her a bit of a stomach ache – and the motion of her kidneys filtering her blood, as well as the impatience of her bladder.

"I told her not to have that cup of tea before we started –"

And then there were other places.

"I'm sorry Illya", Shiro thought again. "But I have to be thorough. I can't leave anything out. It would be too dangerous."

Illya looked at him through the lashes of her half closed eyes as she glanced over her shoulder.

Shiro felt his own heart skip a beat.

Diving further still, his tracing became like a microscope as he moved down – down – all the way to the cellular level. A sudden thrill went through him as he realized he could go even farther. Who knew what the limits were to this power? He might see atoms, witnessing the motion of electrons in orbit, like planets around a star, or finally prove or disprove the quark theory. With this excitement there came a fear – the gulf that opened up below him seemed bottomless.

If the universe were expanding – infinitely vast – who was to say that it wasn't also contracting – infinitely small? Like a line spreading out in both directions, it could go on forever. Shiro was filled with a wild terror that if he started down this path, it would never end.

As exciting – and frightening – as this was, his business was elsewhere.

Looking past the nucleus, with its libraries of all the things that made Illya Illya, he searched one of the cells, ignoring the cytoplasm and the endoplasmic whatever-or-other whose names he couldn't remember because he'd fallen asleep that day in class after staying up all night in his workshop. He searched until he found what he wanted.

Floating off by itself, the little purple structure was shaped vaguely like a kidney bean.

"The mitochondria is the powerhouse of the cell!" his textbook had cheerfully announced, the caption accompanied by a series of pictures purporting to show how the cellular structure worked.

Shiro remembered reading how the inside was filled with a series of inner walls that wound back and forth, giving more surface area for the chemical reactions to work on. Looking inside, he was surprised to find that it was true – the inner walls wove back and forth like a tiny maze – not unlike the pathways of a magic circuit . . .

He also remembered reading in the pages of a science journal he'd been looking at for a research paper that the mitochondria had their own strands of DNA, and that some recent findings suggested that they might be the key to determining the aging process.

"This is it – if there's something killing the homunculus half of Illya, some sort of 'clock' that has an expiration date – it has to be here", he thought, stretching out his arm.

"Trace on!"

"Shiro, saving one person generally means not saving someone else . . ."


All around him the night air was chill, a sharp contrast with the heat of the flames, which sizzled every now and then from the sprinkling of the rain.

"Just one – please let me save just one –"

Kiritsugu's voice echoed against the rippling of the flames.

"Was this how you felt?"

"He's alive! Oh thank God he's alive!"

He looked – happy. So very happy.

"I can't die like this! I haven't even saved one person yet –"

His own words when Lancer's spear had pierced his heart.

"Oh no! Not you! Of all nights, why did you have to be here now? Why did it have to be you?"


Rin sounded like she was crying. Suddenly he heard her voice again, much calmer now, as he remembered a conversation they'd had just the day before.

"The first thing we'll have to do is call the local temple. Your friend lives at Ryudo – or if she wants a foreign funeral, we can contact Kotomine. That's what we did when –"

A pained look came over Rin's face.

"Anyhow, I don't think we should rely too much on those Einzbern homunculus. When the time comes, we had better be ready to deal with it ourselves."

"I can't be angry with Tohsaka", Shiro thought. "She's always there for me, and she's only trying to help."

The pamphlet Rin had left with him listed several options for services in different styles. There were no prices – that would have been vulgar. But it did list approximate wait times at the crematorium based on age – an hour and a half for an adult, 30 minutes for an infant, 45 for a child. How long would Illya take?

"She's so small –"

"Do you think we should have her in a kimono?" Rin had asked. "Or maybe her white dress? There's her purple coat, and she could be wearing her hat – or we could put it under her head, like a pillow –"

The thought of Illya bundled up as protection against the heat of the flames made him gag.


All around him the landscape changed. Strange, yet familiar, the sky grew dark as a series of gears descended from the low hanging clouds, the inner workings of an unknown mind. A lonely hilltop stretched away into the distance. And everywhere – everywhere, there were swords. Stuck point down in the ground, they had hilts of every imaginable shape and variety. Some had guards that ran straight across, while others swept down; some were plain, while others bore rings, or curved knuckle bows to protect the hand. They ran up the hill, steepling its sides like a thousand church spires, casting long shadows like the crosses in a foreign cemetery.

"Blade Works . . ."

Amidst all their anonymity, Shiro saw several patterns he recognized – the blue and gold luster of a sword from a certain legend – the graceful sweep of a katana renowned for its ability to perform a swallow tail strike – and off to the side, a familiar pair of crossed blades, one white, one black, short and curved, meant to be wielded with one in each hand . . .

"I see you've learned to summon it at will."

Shiro turned to face the silver haired ghost who addressed him.

For a moment he and the man in the red coat regarded one another in silence.

"Out on another pointless crusade?"

Shiro turned to the side and glowered.

"I didn't come here to be lectured by the likes of you –"

"But you DID come here . . ."

Shiro sighed.

"Shiro Emiya", Archer said, his voice growing suddenly stern. "I've told you before: you are not one who fights. You are one who creates. When confronted with an enemy more powerful than yourself, you must imagine something that will allow you to overcome it."

"Yeah, I know . . ." Shiro said. He'd heard all of this before, and was in no mood for Archer's condescending arrogance. But still, there was something in his words that he couldn't quite ignore.

"Something that will allow me to overcome the thing that's killing Illya . . ."

A sudden realization came into his eyes.

"That's it!" he shouted, rolling up his sleeve to reveal the green lines of his magic circuit glowing along his arm.

"Trace on!"

"It has to be here!" Shiro shouted.

But what would it even look like?

"Probably something in her DNA", he thought, narrowing his focus to the peculiar little double helix. "Adenine – guanine – cytosine – I can't read this ! I need something simpler – a date, or a calendar, or –"

Suddenly a shape floated up before his eyes. Its lines were so familiar, so mundane, that under other circumstances it would have been laughable.

A round face, set with a dozen numerals, and a pair of hands, the longer of the two pointing to the Roman number X, while the shorter was only an inch away from twelve.

It was ten minutes to midnight.

"A – clock . . ?" Shiro asked, clearly exasperated. For a moment he stared in disbelief. And then he began to laugh.

"This is what I can't stand about 'magic' – it never makes any sense! If we're going to be all modern, with circuits and pathways and stuff, then why on earth would it have to be an old analog clock? Couldn't it at least be a digital one?"

Archer sighed.

"Kids these days – always wanting everything handed to them. A digital clock wouldn't work. There wouldn't be any place to put your hands."

"Place to put my –"

Shiro's eyes travelled to the clock face, as the minute hand ticked one notch closer, bringing the time to 11:51.


Rushing over, he took hold of the two arms.

It was as if he had picked up a sky scraper.

"UGGHHH!", he groaned at the sudden weight. How could one small life be so heavy?

Setting his feet against the IV that in the peculiar old alphabet marked the four, he walked backwards, up the curved inner wall to the three, and pushed with all his might.

As if to answer, the clock ticked again, moving another minute closer.


Shiro screamed as his spine was compressed. But his own pain was the least of his worries. Somehow he knew, without being told, he just simply knew that at midnight, when the two hands met, Illya's life would end.

"No . . ."

Kiritsugu's voice fluttered up to him from somewhere far away.

"That's the thing about being a 'hero of justice'", he said sadly. "No matter how hard you try, in the end you can only save the people from your own side –"

Did saving Illya mean that someone else had to die?

"No –"

Did Illya have to die so that someone else could live?"


Someone like Sakura? Or Tohsaka?

"I'm not playing your game!"

The clock ticked another inch closer to midnight.


A green wave swept over the round face, tracing the arms, the numbers, the gears inside – everything.

"There has to be some weakness –"

As if to mock him, the arm moved again, slicing into his hands.

Only five minutes left.

Shiro's hands pulled away, now slick with his own blood.

The clock remained as it was, motionless.

It was the lack of motion that made him pause.

"That's it!"

Archer looked over, curious at his sudden enthusiasm.

"The long arm doesn't move incrementally", he said, changing the position of his hands and feet, not caring about his wounds. "That's all done by the gears inside. They're the ones keeping track. The long hand only moves once each minute, to record the new time –"

And here Shiro began to pull –

"Illya dies at midnight", he growled through clenched teeth. "But what if the hand never stops at twelve?"

"Damn you're stubborn –" Archer said, setting his hands on the other side as he began to help him push.

"Her homunculus half doesn't exist after twelve. From that point on she's just a regular girl –"

The minute hand began to move –

"I haven't – given up – on saving everyone –"

Shiro could feel his back decompress, and his muscles tearing inside of him, but he didn't stop.

By now, the Blade Works had disappeared around him, with its gears and swords, replaced by the wreckage from that night, and the roaring flames.

"But maybe –"

The clock's hands drew even with twelve.

"Just for tonight –"

Shiro pulled with all his might, not caring if he tore a hole in the universe and uncreated half of the world in the process.

"I'll settle for just one!"

The minute hand surged forward: 12:01 – 12:02 – 12:03 –

Illya cried out.

"Ugh – Shiro, you're –"

Suddenly he became aware of his surroundings again – the room, the chairs, Illya in his arms. She was sitting with her back to him, his arms around her waist. His hands were filled with a gentle warmth. Something seemed to pour into them. The sensation was like nothing he'd ever known – almost liquid, but not quite, as though he were holding two bundles of melting silk.

But it was the softness that stood out to him the most. Never in his life had he felt anything like it. Everywhere he touched was impossibly soft and warm, all except for two hardened points right in the middle.

With a start he realized that he was holding Illya's breasts!

"Um, Illya, I –"

Illya turned to look at him, then just as quickly turned her eyes to look away again.

"E – e – e . . ."

"Why am I holding Illya's boobs!?" he thought to himself, desperately trying to understand the situation. "And how did they get so big!?"

For that matter, everything about Illya had grown – she was several inches taller, her hair was several inches longer – her breasts were several cup sizes larger –

"Of course!" he thought, "The clock! When I pulled the hands past midnight, time moved forward, and Illya moved forward with it!"

Was this what Illya looked like in the future? He didn't have much time to wonder, because before he could think any further into it, he felt the two hardened points again, digging impatiently into each of his hands.

"Hey, why are your –"

"Look, it's cold in here –" she lied.

What should he do? Should he let go? Or would that be rude, as if to imply that he did not want to touch them? Perhaps he should give them a good squeeze –

Just then they heard the sounds of a key turning in the lock.

"Oh Shiro, we're home –"

"It's good to see you Master –"

Rin and Saber stopped dead in their tracks.

Illya giggled nervously.

"Eh – heh – heh – heh . . ."

She moved to pull away from him, but as she burrowed her back into his chest, she realized that with her shirt hiked up, if he let go, she'd be completely exposed, so she leaned forward again, but that only pushed her breasts even further into his hands.

"Ohh –" Shiro groaned, feeling a sudden weight as Illya's breasts grew heavy, hanging away from her chest and coming to rest more fully in his hands.

"Lady Tohsaka, please draw a magic circle. I'm going to kill Shiro, after which I will find myself in need of a new pact –"

"Saber, wait, I can –"

"EX –"

Saber shouted, beginning to summon her noble phantasm, but Rin laid her hand on her arm.

"Now, now Saber, let's not be too hasty. I'm sure there's a perfectly good explanation for this – right Shiro?" she said, turning to him with a smile that was far more terrifying than Saber's attack.

"Mmm hmm, mmm hmm – that explains it", Rin said, after Shiro had finished speaking. "That's sounds like something stupid enough that you would do. Illya appears to be unhurt –" she said, her voice trailing off as she glanced over to where Illya stood in one of Shiro's white shirts with blue sleeves, poking the side of her breast and chuckling at the ripples it produced.

"Are you satisfied, Saber?"

Saber folded her arms and turned to the side.

"Well, Irisviel was very well endowed, so I guess it's only natural, what with Illya being her daughter . . ." she said, her voice still a bit sour.

"Yes, well, I suppose it can't be helped. Court adjourned. Our prisoner is dismissed."

"Whew –"

"You should count yourself quite lucky. If I didn't like your explanation, I was going to let Saber kill you, and then dispose of whatever was left by throwing it down into the training room in the Matou family basement –"


"As it is, I'm actually rather impressed."

"What do you mean?"

"It's time magic", Rin said, clapping her hands behind her back as she looked out one of the windows into the open courtyard of the Emiya family estate.

Saber gasped.

"That's what Kiritsugu used – he had the ability to speed up and slow down time."

"It's very dangerous – you could have been killed."

Rin squinted at Shiro out of one eye.

"Why are you looking at me like that? Is there something wrong with my face!?"

"For a second rate mage who keeps telling everyone that strengthening magic is all he can do, you certainly do have a lot of abilities. I'll remember that the next time we duel . . ."

"Wait – we're going to have another duel!? I thought we were past all that!"

"But of course", Rin smiled, raising her sleeve to reveal the glowing green lines of the magic circuits in her arm. "It's what we mages do."

"Urk!" Shiro said, once again in fear for his life.

"But perhaps another time", Rin answered, rolling down her sleeve, and sticking out her tongue.

"For now, I'm going to take Miss Illyasviel shopping, since she seems to be in need of some new clothes.

'Come along Illya – I know of several boutiques where you should be able to get everything you need. We'll pick up dinner on the way home, since I doubt after all that's happened any of us are going to feel much like cooking."

"Whew – " Shiro sighed after the door had shut. He heard the sounds of Illya's sing song voice as she skipped away into the distance with Rin trailing behind, admonishing her.

It was then that he felt a familiar pair of glaring green eyes boring a pair of matching holes directly into him.

"Look, Saber –" he began, but as he turned to face her he was taken aback by the sternness of her expression.

"Yikes! She's really mad about this –" he thought, trying to figure some way out of the situation. In the end, he decided it was best to simply be honest.

"Look, I – I'm sorry . . . I shouldn't have done anything without talking to you first. Tohsaka's right – it could have been dangerous. The Holy Grail War may be over, but you're still my strategist, and my partner. It was dumb for me to go off on my own, and I'm sorry . . ."

"I'll forgive you – on one condition."

"Sure, anything!"

Saber put her fingers to her chest, just under her chin, and turned away shyly.

". . . . ."

"What's that?"

"M . . . m . . . . . . . . . . . . . . . . . . . . "

"Saber, I can't understand you –"


"What – wait – Saber, no! I can't just – there are things that go into this – like genetics!"

"I DON'T CARE!" Saber shouted, already unbuttoning her shirt.

Shiro reached to stop her, but she grabbed his hand, pulling his arm over her shoulder as she turned her back to him.

"Ack!" Shiro groaned, pulling back with all his might to avoid being judo flipped over her shoulder as she clamped his hand onto her breast.

He could feel the soft lace of her bra, its floral texture rough in comparison to her even softer skin –

And then, for the second time, he heard the sounds of a key turning in the lock.

"Oh Shiii – rooo, I'm hooome", Rin called, unable to say exactly why she took such peculiar delight in the words as she leaned against the door, a plastic bag of Styrofoam containers dangling from one hand as she reached down to remove her shoes with the other.

"It was later than I realized and the stores were all closed, so Illya and I decided to just get dinner and try again tomorrow. I hope you don't mind ramen –"

At the sight of Shiro and Saber together, Rin froze.

"Okay, now I'm pissed!" she shouted, throwing her brown school loafer with deadly precision so that it struck Shiro full force in the stomach, knocking the wind out of him.


"What the hell were you thinking!?"

"Look Rin, I can –"

"And after I gave you my most precious jewel!"

Saber's ears perked up.


"No, Saber, I –"

"EX –" Saber called, her magic sword appearing in her hands.

"Rin – you've got to help me –"

Shiro turned to Tohsaka only to find her pulling out a handful of her explosive magic gems.

"CAL –"

Saber continued her incantations, a whirlwind forming around the blade.

Desperate, Shiro held up his arm.



Narrator: Hi, my name is Kirei Kotomine, and in addition to being the priest who oversees the Holy Grail Wars, due to a series of strange events and a large debt incurred at the local curry shop, I'm also the narrator for this show – what's that? We're on?

Ahem – next time on Fate, Stay Night: Copping A Heaven's Feel – wait, what? Really!? You REALLY expect me to say that!? That does it – I quit! I'm going back to the agency and getting a new narrating gig – maybe something with some frogs, or a nice World War II period piece about some magical girls who fly around fighting aliens while not wearing any pants.