I woke up slowly, the morning light filtering through the cheap curtains. For a second, I forgot where I was.
'Right…'
The futon was surprisingly comfortable. I stretched, feeling the satisfying pull in my muscles. 'Man, I actually slept decently.'
I rubbed my eyes and shuffled to the bathroom. The floor was cold under my feet. 'Note to self: buy slippers.'
When I saw the toothbrush and toothpaste on the sink, I actually smiled. 'Thank god past-me had some common sense.' The minty freshness was the first genuinely normal thing about this morning.
The shower felt amazing. Hot water washing away the last bits of sleepiness. 'Okay, this is nice. Maybe today won't be complete chaos.'
I dried off and got dressed without thinking, just grabbed the shorts and t-shirt I'd bought yesterday. 'Should be fine for a jog.'
The moment I stepped outside, I regretted everything.
'OH COME ON! It's freezing!'
I hugged myself, shivering as the cold morning air bit through my thin clothes. My teeth actually chattered. 'Why is it so cold? This is supposed to be Japan, not Antarctica!'
I made it about twenty steps before turning around. 'Nope. Not happening like this.'
Back inside, I changed into the only long pants I had—some basic sweatpants—and threw on a hoodie. 'Better. Still basic, but at least I won't get frostbite.'
I headed out again, this time actually able to focus on jogging. The streets were quiet, just the sound of my breathing and footsteps. 'Okay, this is better. I can work with this.'
As I ran, my mind started wandering. 'I really need more clothes. And maybe a proper tracksuit. And food. And… pretty much everything, really.'
I passed a convenience store and made a mental note to stop there later. 'Clothes first, then supplies. And coffee. Definitely coffee.'
I turned down a quieter residential street, my breath making little clouds in the air. That's when I saw him.
A young man, maybe early twenties, with messy brown hair. He was walking leisurely, swinging a small paper bag and humming a tune. He looked utterly ordinary.
My feet slowed to a stop.
I knew that face. I'd seen it in character profiles, in anime stills, in the darkest corners of the Type-Moon wiki.
Ryuunosuke Uryū.
The serial killer. The future Master of Caster. The man who turned child murder into "art" with Gilles de Rais.
A cold, sharp feeling—not fear, but pure, undiluted revulsion—washed over me so completely it felt like the temperature dropped another ten degrees.
'Kill him.'
I didn't question it. I didn't hesitate. In a world of magic and grail wars and heroic spirits, some evils were too absolute to risk.
He noticed me standing there and offered a friendly, vapid smile. "Oh, hello! Lovely morning, isn't it?"
I made my own smile appear. It felt like pulling a mask over a stone face. "It is. A bit cold for me, though. I'm Kenji. New around here."
"Ryuunosuke!" he said, his eyes lighting up with a vacant cheer. "A new face! How exciting. Fuyuki is so dreadfully boring sometimes. It needs… new colors."
'New colors.' My skin crawled. I knew exactly what "colors" he was talking about.
"I was just thinking the same thing," I said, my voice calm, conversational. I took a step closer. "It's hard meeting people. You seem friendly. Want to hang out? Show me around?"
His expression brightened with genuine, grotesque delight. "Really? You'd want to? Most people… they don't understand my perspective. They call it sick." He pouted slightly, like a child denied a toy.
"I'm a good listener," I said. The cold inside me was now a focused, humming thing. I gestured down the alley we were near. "I saw a really interesting mural down this way. Wanna see?"
"Oh! Lead the way!"
I led him into the narrower alley. Up ahead was the delivery entrance to a closed electronics store, its metal shutter down, but a large, pristine mirror was mounted beside it for decoration.
"Here," I said, stopping in front of it. Our reflections stared back—a blonde teenager in a hoodie and a smiling man in a windbreaker.
"Hm? It's just a mirror," Ryuunosuke said, tilting his head.
"Look closer."
I shoved him, hard, in the center of his back.
He yelped, stumbling forward—not into the hard wall, but through the glass as if it were the surface of a pond. The reflection rippled and swallowed him. I stepped through right after.
The world inverted into the muted, silent grayscale of the Mirror World. Ryuunosuke was sprawled on the ground, his cheerful confusion rapidly twisting into panic as he looked around at the dead, hollow echo of the alley.
"W-what is this place?! What did you do?!"
I didn't answer. My eyes went straight to the backs of his hands. 'No Command Seals?'
That made this simpler.
"You said you liked new colors," I said, my voice echoing flatly in the stillness. "Let me show you my favorite."
I reached to my side where the Zolda Advent Deck rested. The action was smooth, decisive. I flipped it open.
"HENSHIN."
Green light erupted. The cards of light swirled, and the armor assembled around me in a cascade of mechanical seals and plates. The weight of the armored suit settled, the bull-horned visor clicked over my face, and the massive shoulder-mounted Shoot Vent cannons locked into place with a heavy, final clunk.
Ryuunosuke scrambled backward, his eyes wide with a terror that was almost beautiful in its purity. "A… a monster…! A real one!"
'No,' I thought, the reticle in my visor painting a bright, steady dot on his forehead. 'You're the one who makes monsters. I'm just the cleanup.'
I didn't give him another second to speak. I didn't want to hear his voice again.
I raised Zolda's right arm, the barrel of the massive gun glowing with a soft, green charge.
I pulled the trigger.
VWOOOM-CRACK.
The sound wasn't a gunshot. It was the sound of compressed space and force being released. The green energy bolt hit him squarely between the eyes. There was no explosion, no fire—just a devastating transfer of kinetic energy that snapped his head back and dropped his body to the colorless pavement like a sack of meat.
He didn't twitch.
I stood there for a moment in the profound silence, the hum of my armor the only sound. I looked at the body. No guilt. No doubt.
I turned and stepped back through the mirror, the glass rippling once before becoming solid again.
Back in the real Fuyuki alley, the morning sun felt the same. The air was still crisp. A distant dog barked.
I adjusted my hoodie and started jogging again, my pace steady, my breathing even. I had errands to run.
'Ryuunosuke's dead. Caster's summoning is gone.' I let that sink in, unsure if I should feel relief or dread. 'But without Ryuunosuke, who's going to summon Gilles de Rais? Someone else? Or does the Grail just… pick another Master...how do these isekai people remember so much in those fanfictions?'
'I need to start planning. Avoiding this mess isn't an option now. I've already changed the timeline.' I paused mid-jog, catching my breath.
I spotted another clothing store ahead, its neon sign blinking 'Discount Fashion.' 'Finally. Let's hope this place isn't a rip-off.'
Inside, the racks were crammed with cheap-looking clothes. I grabbed a basic black tracksuit and checked the price tag.
My shoulders slumped. 'Nope. Still too expensive.' I put it back, sighing heavily. 'How am I supposed to survive here if I can't even afford a tracksuit?'
I left the store, frustration gnawing at me. 'Maybe I should go back to beating up thugs for cash. At least that worked last time.' The thought was only half-joking. 'But screwing with gangsters might just draw more attention. And I'm supposed to be laying low.'
I started walking back toward my apartment, mentally calculating how much money I had left. 'Enough for food, maybe. Clothes? Forget it. Supplies? Maybe if I prioritize.'
Then I felt it—a sharp, stinging pain on my right arm, like a needle pricking my skin. I froze, heart skipping a beat. Slowly, I rolled up my hoodie sleeve.
There it was. A red, intricate marking glowing faintly on my forearm. A Command Seal.
'No. No, no, no.' My stomach dropped. 'This wasn't supposed to happen. I was supposed to stay out of this. I didn't even—'
The realization hit me like a truck. Killing Ryuunosuke. Changing the timeline. The Grail had noticed. It had chosen me as a replacement Master.
'Great. Just great.' I stared at the mark, a mix of dread and resignation settling over me.
'...First things first. I need to summon a Servant.' The thought made my head spin. 'If I'm a Master, I need a catalyst. Something meaningful to summon the right Heroic Spirit.'
I walked faster, heading back to my apartment. My mind was already scrambling through possibilities. 'What do I even have? Some random junk from the convenience store? The books I bought yesterday?'
Then it hit me—the Zolda Advent Deck. My Rider transformation item. It was a weapon, a symbol of power, and tied to Kamen Rider lore. 'Could that work?'
I shook my head, trying to clear the jumble of thoughts. 'This is insane. I'm not a mage. I don't know summoning rituals. I don't even know if I have enough mana to sustain a Servant.'
But I didn't have a choice. The Command Seal on my arm was proof of that.
'Alright, Kenji. Focus. Step one: Get home. Step two: Figure out how to summon a Servant without blowing up the apartment. Step three: Pray I don't summon something that'll make everything worse.'
---
I was back in my apartment, breathing hard. My arm itched where the Command Seal had seared itself into my skin. This was not part of the plan. I needed a distraction. I flopped onto my futon and pulled up the group chat. A message was waiting.
[Kobayashi: Good morning, everyone.]
I typed a quick reply, my fingers still a little unsteady.
[Kenji: Morning.]
We exchanged a few lines—her asking about the new city, me giving vague, non-committal answers—before she signed off.
[Kobayashi: I must go. Tohru requires… correction.]
I stared at the message. Tohru? Already? That was fast. Time really was out of sync between our worlds. The thought was unsettling, but I had bigger, more immediate problems. The red mark on my arm pulsed faintly.
I needed a catalyst. Now. Something connected to a Heroic Spirit. My eyes darted around the sparse apartment. I had nothing. No family heirlooms, no ancient relics. Just a convenience store toothbrush and a bag of chips.
'Steal one,' the thought came, cold and practical. It was the only option. I was already a murderer yesterday in another world. What was grand theft on top of that?
I moved to the full-length mirror leaning against the wall, the one I'd bought because the apartment felt too empty without it. I took a breath and flipped open the Zolda Advent Deck.
"HENSHIN."
The green light enveloped me, the mechanical plates of the Rider armor locking into place with a series of satisfying clicks and hisses. The world through the visor was sharper, clearer. I raised a gauntleted hand and touched the glass. It rippled like water. I stepped through.
The Mirror World was its usual self—a silent, monochrome copy of Fuyuki. Sounds from the real world were distant echoes here. I moved through the gray streets like a ghost, using reflections as doorways. I needed somewhere with old, powerful things. A museum? Too fortified. An antique shop… that could work.
I found one after a few minutes of searching—a cramped shop called "Curios & Blades" tucked between a noodle stand and a pachinko parlor. In the real world, an old man was dusting a display case. In here, his reflection moved in slow, silent mimicry. The case held several Japanese swords.
One in particular called to me. It was a katana in a black lacquer saya with golden chrysanthemum motifs. Even in this colorless dimension, it seemed to hold a faint, internal light. 'That's the one,' I thought. It looked important. It looked like a story.
I positioned myself in the Mirror World directly behind the case. Taking a breath, I stepped backward through the glass.
---
30 Minutes Later
---
Reality snapped back with a burst of sound and color. I was suddenly standing in the middle of the shop in broad daylight, seven feet of gleaming green and silver Kamen Rider armor. The old shopkeeper yelped, dropping his duster. A customer by the door screamed.
'No time for subtlety.'
I lunged forward, my armored fist smashing the glass of the display case with a crash. Shards tinkled to the floor. I snatched the katana from its velvet stand.
"Thief! Monster!" the old man shouted, scrambling for a phone.
I didn't wait. I turned and threw myself at the large, ornate mirror hanging on the opposite wall. I passed through it like diving into a still pond, the screams cutting off abruptly as the Mirror World swallowed me again.
In the gray silence of the alley reflection, I slumped against a wall, the katana clutched in my hand. My heart was hammering against my ribs. 'That was insanely loud. And public. I am so, so stupid.'
---
Another 30 Minutes Later
---
Back in my apartment, I dispelled the armor causing the green light to dissipate, leaving me in my sweatpants and hoodie, holding a very... very stolen katana. I placed it on the low table, my hands trembling slightly from the adrenaline crash.
'Now what?' I thought, staring at it. 'I have the catalyst. What's step two?'
Absently, I reached for the remote and clicked on the small TV, needing background noise to quiet my racing mind. The local news channel was on.
"—continuing our top story," a serious-faced anchor was saying. "A brazen daylight robbery has left the Fuyuki historical community in shock."
My blood ran cold. A shot of the shop I'd just robbed filled the screen. Police tape. The broken case.
"The stolen item," the anchor continued, "is not merely a valuable antique. It is the Kiku-Ichimonji, one of the famed swords of the Shinsengumi, specifically associated with the First Unit Captain, Okita Souji. It was on a special cultural loan from Kyoto. Authorities are describing the perpetrator as 'a man in monstrous green armor' and are treating this as a major cultural property theft."
Okita Souji.
The name hit me like a physical blow. I knew that name. The genius swordsman of the Shinsengumi. The one who died young from tuberculosis. A Saber-class Servant… and famously, one of the most physically frail due to her legend being intertwined with her fatal illness.
My initial reaction was a wave of pure dismay. 'A crippled Saber? I'm supposed to fight Kiritsugu, Kirei, and a homunculus with a Servant who's going to cough up a lung mid-battle?'
I sank to the floor, the weight of my own idiocy pressing down on me. I'd panicked, grabbed the flashiest sword I saw, and now I was stuck with a liability. I was going to die because my Servant would be too busy having a haemorrhage to block an attack.
'Her tuberculosis… it's not a biological disease. Not really. Not for a Servant. It's part of her Saint Graph. A conceptual weakness baked into her spiritual existence.'
I sat up straighter. The dismay began to curdle into something else—a sharp, clinical curiosity.
'If it's part of her spiritual construct… can it be erased? '
The thought was electrifying. The Grail System was a miracle of spiritual engineering. Servants were complex programs made of magic and legend. Their Saint Graphs were their source code. And I… I wasn't a mage. But I had something else. I had a System. A foreign, possibly reality-breaking set of rules that had given me the power of a Kamen Rider and allows me to grow and adapt upon seeing things real or fiction.
What if I could use it to… debug a Servant?
'This isn't a disadvantage,' I thought, a slow, grim smile spreading across my face. 'This is a research opportunity. If I can learn to manipulate her Saint Graph, to isolate and suppress the "Tuberculosis" trait… what else could I do? Could I enhance parameters? Modify skills? This could change everything.'
I reached out and touched the lacquered saya of the Kiku-Ichimonji. It felt cool under my fingers. I wasn't holding a ticket to a powerful warrior. I was holding a unique, fragile, and incredibly valuable test subject. A key to understanding the very fabric of Servants.
The renewed purpose solidified my resolve. Okay. New plan. Summon Okita. Keep her alive. Study her. Fix her. The Grail War could wait. This was bigger.
I stood up, the katana in hand, ready to begin.
And then I stopped dead.
A profound, utter blankness filled my mind.
'…How do you summon a Servant?'