Chapter 15: The Horror of Theory
Sunday morning dragged itself to the Emiya Residence with the delicacy of an anvil falling on Shirou's chest. He had barely slept. He had spent the hours in a state of dreadful wakefulness, where every time he closed his eyes, the curtain of his mind replayed, in a relentless loop, the sharpest frames of his nightmare: the flash of the crystal dagger falling, the hooded figure moving its fingers like spider legs, the metallic glint of tubes connected to flesh, and above all, Kirei Kotomine's eyes, serene and empty, as his fingers squeezed.
He dressed mechanically. The feel of his shirt against his skin reminded him of the coldness of that imaginary marble floor. In the kitchen, Taiga yawned at the table, talking about a new ramen restaurant.
— Shirou, are you okay? You look like a ghost— She said, leaning forward to look at him with still-sleepy eyes.
— Just tired, Taiga-nee— He lied, and the taste of the falsehood burned his tongue. It was the first conscious lie he'd told her. Guilt mixed with anguish, forming another knot in his stomach. Then, after eating monotonously, he bid a dull,— See you later— to Taiga and left the house for his next magecraft lesson with Rin, but his feet felt as if he were walking through tar.
The walk to the Tohsaka mansion was a journey through an alien landscape. The sunlight, too bright, seemed to illuminate every corner with a sinister intent, as if wanting to expose the shadows he knew could be hiding there. A pigeon taking flight from a wire made him hold his breath, its flapping confused for a second with the sound of a cloak brushing the ground. He arrived at the door a bit breathless, his hands sweaty inside his pants pockets.
The door opened before his finger could touch the bell. Rin was there, already dressed not in her uniform, but in tight jeans and a loose turtleneck sweater that looked stolen from a much larger closet. Her black hair, for once, wasn't perfectly gathered in her signature twin-tails, but in a low, careless ponytail from which a few rebellious strands escaped. She had a stain of what looked like blue ink on the back of her left hand.
— You're late— She announced, without preamble, but her tone lacked the usual acerbity. It was more of a fact, a point to note on a mental list. She scrutinized him from head to toe with her blue eyes, that hawk-like gaze that registered everything. Shirou saw her right eyebrow, the more expressive one, arch slightly— And you look a mess. Didn't sleep at all? Looks like you got punched in the face with those dark circles.
— A little— Shirou murmured, avoiding her gaze and focusing on the ink stain. For a moment he saw it as red, like the blood spilling from a wound…
He didn't finish the thought, he didn't want to. He squeezed his eyes shut and shook his head quickly, partially recomposing himself.
— Well, today is theory— Said Rin, turning her back and walking inside— If you try anything practical in that state, you're more likely to melt the basement than anything else. Come in.
The main living room was transformed. The low table had been moved aside, and in its place, in the center of the carpet, were several open books, unrolled scrolls held down with crystal paperweights, and a small hand-held blackboard where Rin had drawn a series of complex diagrams that looked to Shirou like hieroglyphs from another planet. There were two steaming cups of tea, but also a half-empty plate of saltine crackers. It was the organized chaos of a brilliant, teenage mind that had been reviewing until the last minute.
— Sit there— Rin indicated, pointing to a cushion on the floor in front of the display— And try to keep your eyes open, at least.
Shirou obeyed, sinking into the cushion. The scent of tea, old paper, and the light fragrance of Rin's shampoo— something with mint— formed a strangely calming, but fleeting, cocktail. As soon as Rin sat in front of him, crossing her legs with feline agility and picking up a long pointer that looked more like a toy magic wand, the tension settled back onto his shoulders.
— Good— Rin began, tapping the first diagram on the blackboard softly. She had the air of a little professor, a mix of pride in her knowledge and impatience at having to explain the obvious— Yesterday you stuck your head in the wolf's mouth and luckily it only bit you a little. Today we're going to learn what the wolf is, why it has a mouth, and if possible, how to keep it from biting your head off in one go. We start with the basics: Magecraft or Thaumaturgy.
Her voice took on a lecturing tone, but not that of a veteran teacher. It was the tone of someone repeating something memorized perfectly, with the unshakable confidence of one who still believes books have all the answers.
— It's not fairy-tale magic. You don't wave a wand and a cake appears— She made a dramatic pause, as if expecting Shirou to note this revelation— It's a system. You use Prana, magical energy processed through your circuits, to trick the world. The world has its rules: gravity, fire burns, the dead stay dead. Magecraft doesn't create new rules. What it does is…— She searched for the word with a frown, twirling the pointer between her fingers— deceive reality. It makes it believe that something which is already possible, but wasn't happening, suddenly is happening, and in the way you want. It's like a magic trick. A very, very convincing one.
Shirou nodded slowly, trying to follow the thread "Deceive reality". His "Miracle" Origin sounded less like a trick and more like kicking over the game table.
— The power for the trick comes from two sides— Rin continued, holding up two fingers— One: your Magic Circuits. The same ones you activated for the first time yesterday. They convert Od: your life energy, your heat, your… well, your life, into usable Prana. The more you use, the more you exhaust yourself. It's physics, not poetry.— The second finger rose.— Two: Ley Lines. They are the Od of the world. Like veins of energy in the planet's body. In some places, like here in Fuyuki, they are thicker, more potent. A magus can latch onto them like a tick and suck energy for big rituals. Very useful, but also very visible to others who might be watching.
"Like a tick". The image was unpleasant. Shirou thought of the hooded figure from his dream, draining Rin. Was that it? A forced connection to a Ley Line? His mind began to wander, Rin's voice becoming background noise as the dream images bared their claws. The ink stain on Rin's hand seemed to vibrate, transforming in his mind into the violet glow of circuits under pale skin.
— Emiya— Rin's voice became sharp— Are you listening or are you planning your next nap?
He blinked, forcing his eyes to focus on her again. Rin was looking at him with her arms crossed, the pointer tapping impatiently against her shoulder.
— Y-yes, legal lines, magus ticks…— he mumbled.
Rin rolled her eyes with an exasperation that was almost comical— They're Ley Lines! And it's not "magus ticks", it's an analogy, understand? A comparison. For heaven's sake…— She sighed, running a hand over her forehead, brushing away that rebellious strand— Look, this is important. Where you're standing matters. Fuyuki is a nexus of lines. That's why things happen here. Things like the Holy Grail War.
The name fell between them like a block of ice. The air seemed to cool several degrees. Shirou felt a chill run down his spine. It wasn't just a word; it was a concept he had witnessed in his most chaotic visions, associated with the promise of battle and blood.
— The Grail…— He murmured, involuntarily.
— Is an artifact— Rin cut in, her voice instinctively dropping in volume, as if the living room walls could have ears— A gigantic magical system. It's said it can grant a wish, reach the Root of All, the origin of everything in this world. But to activate it…— She paused, chewing the inside of her cheek, a nervous gesture— it needs a stupid amount of energy. The energy of…
— … of defeated Servants— Shirou completed in a whisper. He remembered. Fragments of conversations between blurry and other known figures. "The harvest of souls".
Rin went completely still. The mask of the little professor cracked, revealing an expression of genuine surprise and, beneath it, a hint of unease.
— How…?— She began to ask but stopped herself. She swallowed and nodded, forcing her face back to neutrality— Yes. Seven magi, seven Servants. A secret war. The winner gets the wish. The losers… well, most stop being a problem. Forever.
The phrase "stop being a problem" echoed in Shirou's mind with a sinister coldness. It wasn't an adult, cynical euphemism; it was the clumsy, hard way a girl who had grown up with that truth tried to verbalize it. Shirou didn't see strategy in her words; he saw the reflection of an ancient fear. And suddenly, the violet glow from his dream, the draining, took on a new meaning. Was that what happened to people in such a war? Did they become… fuel?
A cold sweat beaded on the nape of his neck. Rin's voice continued, but now she was talking about Magical Foundations, the system of beliefs that shaped spells, about the Tohsaka's based on Conversion of Power. Shirou nodded, but the words slid off him. "Conversion." "Transmutation." His mind twisted them. He saw Rin's blood in the cave, turning into a dark puddle. He saw her vitality in the temple, transmuting into that violet glow escaping her. The theory was no longer abstract; it was the instruction manual for his own nightmares.
— …and that's why the Magic Crest is crucial— Rin was saying, showing her own hand, where complex silver lines glowed for an instant— It's not just power. It's my family's history. Every spell, every achievement, engraved here. It's… an obligation— Her voice darkened for a moment— You don't have one. You're a First Generation. You have freedom, but you're also alone. Without the wisdom of those who came before…
Shirou no longer saw her. He saw the gray room from his dream, the Rin turned into a statue connected to tubes. Was that a Crest? An obligation that emptied you until you were a husk? A nauseating dizziness washed over him. The living room seemed to tilt. Rin's voice became the buzzing of a trapped fly.
—… which brings us to the Principle of Non-Interference. The Mage's Association, the Clock Tower, forbid exposing the magical. If you do, you become a target and get a Sealing Designation, to later be hunted by Enforcers. For people with secrets like yours, it's…
— ENOUGH!
The word exploded from Shirou's lips with a force that burned his throat. It wasn't a thought-out shout. It was a spasm, the final eruption of all the pressure, fear, and pent-up rage. He jumped to his feet, making the teacup beside him rattle. The cracker Rin was about to take fell from her hand, crumbling onto the parchment.
Rin froze, her hand still extended, her eyes wide as saucers. It wasn't the look of a teacher angry at an interruption. It was the look of a twelve-year-old girl who had just been suddenly yelled at, startled, and for an instant, scared.
— E-Emiya?— She managed to say, her voice losing all its affected confidence.
— I can't…— Shirou gasped, bringing a hand to his head as if he could knock the images out with a blow— I can't hear about principles or… or interference, when… when last night…— He looked up at her, and in his amber eyes, now bright with raw, unfiltered anguish, Rin didn't see the troublesome student. She saw a terrified child— I saw you die, Rin! Again and again. And it wasn't… it wasn't vague. It was real! I could smell the blood! I could feel the heat leaving you! And in one, Kirei… Kirei snapped your neck and you could hear…!
— SHUT UP!
It was Rin's scream that cut the air this time. A sharp scream, loaded with panic. She had also stood up, pushing the small blackboard, which fell sideways with a dry thud. Her face, once slightly flushed from concentration, was now pale. Her eyes showed not anger, but terror. An animal, recognizable terror.
— Don't say that!— Her voice trembled, almost pleading— Don't shout it! Are you crazy?— She lowered her voice immediately, looking toward the living room door with paranoia— If someone… if he… You can't go around saying those things!
Shirou watched her wring her hands, the same nervous gesture of chewing the inside of her cheek, but now intensified. He had scared her. Truly. Not with his power, but with his words. With the possibility they represented. Seeing the always-confident Rin Tohsaka like this, vulnerable and frightened like any girl, was a bucket of cold water that calmed the fire of his own panic a little, leaving only ashes of guilt and a deep cold.
— But it's the truth— He insisted, in a much lower, broken tone— They were visions. Like the ones before. But this time it was you. In a cave, with something… with a figure of shadows and white hair… it stabbed through you. Then in a temple, a hooded figure hung you up and emptied you, your circuits were glowing and you were screaming… and then Kirei. I saw it clearly. As clear as I see you now.
Rin said nothing. She breathed through her nose, fists clenched at her sides. The fear in her eyes was waging a fierce battle against pride, the need for control, and the cold logic she always tried to impose. Logic won, by a hair, but it was an adolescent logic, cracked.
— They're… possibilities— She said finally, her voice still trembling but trying to find firmness— Echoes. The future isn't written— She was repeating the mantra to herself as much as to him.
— Then why do I see them?— Shirou's voice was a whisper laden with desperation— To drive me crazy? So I know all the horrible ways that… that you can…?
He couldn't finish. The word "die" got stuck in his throat, too big, too final.
Rin averted her gaze, fixing it on the parchment stained with crumbs. Her profile, normally so defiant, seemed younger, more fragile.
— The magical world…— She began, and coughed to clear her voice— is not a safe place, Shirou. What you've seen… are the dangers. The real dangers. They aren't scary stories for children— She looked up, and this time she looked directly at him with a feverish intensity— But that's why you're here. That's why I'm teaching you! Do you think I bore you with theory for fun?— Her voice rose again, but now with a genuine, almost desperate frustration.— It's because theory is the antidote! The dream shows you the poison: "here's a cave, here's a monster, here Kirei is a traitor"! And theory gives you… it gives you the map to not enter the cave, the name of the monster to know how to avoid it, the history of the Executors to know what Kirei is capable of!
It wasn't an elegant speech. It was a torrent of broken words, of rage and fear turned into argument. She pointed an accusing finger, not at him, but at the diagram of the basic magical circle on the fallen blackboard.
— That circle! That energy-dissipation circle I didn't get to finish explaining! If someone… if a hooded figure tried to drain you with a suction spell, activating this in time could create a field of rejection. It's not an infallible shield, but it's something! It's more than just standing there, paralyzed, watching it happen like in your dream!
Shirou followed her gaze. The diagram, once a jumble of incomprehensible lines, began to make sense. It wasn't just a drawing. It was a set of instructions. A tool. A small, fragile possibility of change.
— Theory isn't rules for a boring game— Rin said, lowering her voice again, a sudden weariness in her shoulders— They are the survival rules of the world we've stepped into. And if you…— She paused, swallowing— if you freeze in fear, then I… I'm lost too. Because you are…— She searched for the word, rejecting several with a frown.— a variable. A huge, dangerous variable. And I need that variable to know enough to not… to not set off all the traps at once.
It was the most selfish, practical, and honest reasoning she could offer. It wasn't "I'll help you because I care about you". It was "I'll teach you because if I don't, you'll endanger me". And somehow, for Shirou, that bluntness was more comforting than any false promise of protection. It was a pact between equals at the bottom of a boat: row or we both sink.
The silence that followed wasn't comfortable, but it was no longer charged with panic. It was filled with the acknowledgment of an uncomfortable, shared truth. Shirou took a deep breath, feeling the cold air fill his lungs, dispelling some of the fog in his mind.
— So?— Rin asked, arms crossed, recovering a hint of her usual attitude, though her gaze was still more vulnerable than normal— Are you going to keep standing there staring into space, or are you going to sit down and we'll see how to activate that dissipation circle? Because if it's the former, the door is there. But if you leave, don't come back asking me for lessons when your next nightmare comes true because you didn't know how to avoid it.
It was an ultimatum. A challenge. And exactly what Shirou needed. A clear point to move toward, away from the paralysis of fear.
He sat down slowly, sinking back into the cushion. His hands no longer trembled.
— Teach me the circle— He said, his voice firm for the first time that morning.
Rin stared at him for another second, as if assessing his resolve. Then, with a sigh meant to sound annoyed but which sounded more like relief, she picked up the blackboard from the floor, wiped off the broken chalk with the sleeve of her sweater— soiling it further— and sat in front of him, much closer than before.
— Fine. As I was saying, before "someone" had a hysterical fit…— She began drawing again, explaining each line, each symbol with renewed concentration. Her knee, inadvertently, brushed against Shirou's under the low table. Neither of them moved their leg away.
The lesson continued. The fear hadn't disappeared. It was still there, sitting between them like a silent third guest. But now, instead of paralyzing them, it had united them in a common, tacit purpose: to learn to defend themselves, not just from the world, but from the futures that fear painted for them in the dark. And for the first time, Shirou didn't just listen to Rin's words, he saw them: not as dry theory, but as the first, fragile, and essential bricks of a wall that, hopefully, would be strong enough.