Chapter Text
A groan escaped Ritsuka’s lips, their head throbbing in a dull, persistent rhythm against the cold stone floor. The scent of damp earth and something cloyingly sweet, like overripe fruit and sake, filled their nostrils. Pushing themself up onto their elbows, they took in the surroundings. They were in a cave, the only light coming from a single, eerie purple flame dancing atop a gourd-shaped bottle. A sharp pain shot up from their ankle when they tried to move, forcing them back down with a gasp.
“Ah, you’re finally awake, little human.”
The voice was like honeyed wine, smooth and intoxicating, yet with a dangerous undercurrent. From the shadows, a figure emerged. A woman with horns peeking from her lavender hair, clad in a revealing outfit that left little to the imagination. A mischievous, almost predatory, grin played on her lips as she knelt beside them. It was Shuten Douji.
“Don’t try to move too much. Your ankle was a mess, but I patched it up for you,” she purred, her finger tracing a light pattern on their cheek. “You took quite the tumble.”
Ritsuka flinched away from her touch, memories flooding back. The mountain peak, Raikou’s fury, and then… falling. “Onui… Tasuke… where are they?”
Shuten let out a musical laugh. “The little ones are with that brute, Raikou. She kicked me all the way down here for wanting a little taste. Can you believe the nerve?” She leaned closer, her crimson eyes boring into theirs. “But forget about them. I’ve taken a liking to you. Stay with me, become my plaything, and I’ll give you anything your heart desires. Power? Riches? Pleasures beyond your wildest dreams?”
Ritsuka’s jaw tightened. The only thing they desired was the safety of the children. “Give me back Onui and Tasuke. That’s all I want.”
Shuten’s smile widened, but it didn’t reach her eyes. The playful warmth vanished, replaced by a chilling coldness. “No, I don’t think I will. They’re no fun. But you…” she giggled, a sound that sent shivers down Ritsuka’s spine. “You’re far more interesting.”
Before Ritsuka could react, her hand shot out, fingers sharpened like claws, and plunged into their stomach. The pain was blinding, a white-hot agony that stole the breath from their lungs. They tried to scream, but only a choked gasp escaped.
“Oh, don’t look so scared,” Shuten cooed, her face alight with a twisted glee. “I just want to play with your Magic Circuits. Let’s see what makes you so special.”
Ritsuka could feel her tearing into them, a horrifying sensation of being unmade from the inside out. Their vision blurred, the purple flame of the gourd multiplying and swimming before their eyes. Shuten’s laughter echoed in the cave, mingling with their own silent screams as unconsciousness finally claimed them.
High on the mountain peak, the wind carried a different sound—the soft notes of a lullaby. Minamoto no Raikou held the sleeping Onui in her arms, gently rocking the child who had cried herself to sleep. Tasuke sat nearby, watching with wide, curious eyes.
Onui stirred, her small voice joining the melody in her sleep. “…Mom…” she murmured, nuzzling closer to Raikou’s chest.
The song caught in Raikou’s throat. She froze, her expression unreadable. Onui’s eyes fluttered open, and she immediately scrambled back, her face flushed with embarrassment. “I-I’m sorry! I didn’t mean…”
Raikou offered a rare, small smile, though it was tinged with sadness. “It is alright, little one. You need not apologize for a dream.” She looked away, towards the moonlit clouds. “But do not lower your guard around me. You must not forget that Shuten and I… we are oni. Two of the most wicked creatures to walk this land.”
“But you saved us,” Tasuke said, his voice small but certain. “You remind me of our mother. She was strong and kind, just like you.”
The innocent comparison struck a chord deep within Raikou. Her hand instinctively went to the hilt of her katana, her motherly instincts flaring into a fierce, protective inferno. Her gentle demeanor vanished, replaced by the sharp, focused gaze of a warrior.
“Stay here, and do not move,” she commanded, her voice low and serious. She could sense it—a familiar, corrupting presence on the wind. Something was wrong.
Down in the cave, the others finally found him. But the person lying on the cold stone was not quite the Ritsuka they knew. Their skin was paler, their expression held a hint of Shuten’s cruel smirk, and when they spoke, their voice had a faint, musical lilt that was disturbingly familiar. The oni’s influence had already begun to take root.
With a violent jolt, Ritsuka’s eyes flew open. They were in their bed, the sterile white ceiling of their room in Chaldea a stark contrast to the oppressive darkness of the cave. Their heart hammered against their ribs, the phantom sensation of claws digging into their stomach still achingly real. A cold sweat slicked their skin.
It was just a dream. A nightmare.
Their gaze fell on the digital clock by their bed. The glowing red numbers read: 8:00 AM, October 31st.
Shaking off the lingering dread, Ritsuka swung their legs out of bed. The dream felt too real, a visceral memory that made the hairs on their arms stand up. They quickly got dressed, the standard Chaldea uniform feeling like a thin shield against the madness Halloween was sure to bring. Just as they finished, a sharp knock echoed through the room.
Ritsuka opened the door to a sight that made their blood run cold. Two Shutens stood there, grinning. One was the familiar, dangerously alluring Assassin, her horns and sly smile a direct pull from the nightmare. The other was a Caster version, dressed in a frilly, vibrant magical girl outfit as ‘Oni Cure.’ They were a bizarre and terrifying pair.
In perfect, rehearsed unison, they sang a little jingle, their voices blending in a sickly-sweet harmony. "Trick or treat, Master dear! A special gift, just for you this year!"
The Assassin Shuten held out a small, ornately wrapped piece of candy. Oni Cure held a steaming, mysterious drink in a delicate cup.
"Which one will you take?" the Assassin purred. "The trick or the treat?" Oni Cure chirped. "Who can say which is which?" they said together, their crimson eyes sparkling with shared mischief. "Only one way to find out!"
Ritsuka’s mind raced. After that dream, every instinct screamed at them to slam the door. But this was Chaldea, and these were their Servants. Refusing could be just as dangerous. They eyed the two offerings. The drink looked far too suspicious. The candy… the candy seemed safer. "I'll... go with the candy," Ritsuka said, their voice barely a whisper.
The Assassin Shuten’s smile widened. "Sweetie, you are so cute when you look so worried," she crooned, stepping closer. "Why so scared? I know I'm an oni, but I haven't done anything!"
As Ritsuka reached for the candy, Oni Cure giggled and, in a flash, dipped the candy deep into the drink, coating it in the strange liquid. She held it out, now dripping, directly in front of Ritsuka's lips. "Make sure to swallow it all, sweetie!" she said, her smile unwavering. "By the way, the trick is the treat."
Before Ritsuka could protest, the candy was pushed into their mouth. As they instinctively swallowed, the Assassin leaned in and placed a soft, cold kiss on their cheek.
The potion's effect was instantaneous. It wasn't just heat; it was liquid fire pouring through their veins, starting from their core and branching out to every extremity. Ritsuka cried out, doubling over and clutching their stomach as their legs gave out. "Ugh! Ah! What is this... What did you do?!" they choked out, their body trembling uncontrollably.
"Oh, the best part is just getting started, sweetie," the Assassin Shuten purred, catching Ritsuka before they hit the floor. She held them steady, her touch surprisingly gentle. "Just relax and let the potion do its work. It knows what to do."
"Look, look! It's working!" Oni Cure bounced on the balls of her feet, clapping her hands. "The potion is rewriting them from the inside out! See how their skin is getting all pale and smooth? So cute!"
Ritsuka gasped as a sharp, cracking sound echoed from their own frame. Their shoulders narrowed, their limbs slenderizing with an unnatural speed. The standard-issue uniform, once a comfortable fit, began to hang loosely around their arms and shoulders while simultaneously growing uncomfortably tight across their chest and hips. Their jawline softened, cheekbones rising slightly, and their eyes, wide with a mix of terror and confusion, seemed to gain a new, alluring shape, their color deepening into a shade of amethyst.
The Assassin ran a cool hand down their arm, humming in appreciation as their skin lost its healthy tan, paling to a delicate, almost translucent white. "So soft... just like an oni's skin should be. Perfect for touching."
The most intense sensation, however, was centered on their head. A splitting headache was followed by an itching, tingling feeling at their temples that was impossible to ignore. "Agh! My head... it feels like it's splitting open!" They reached up, their fingers brushing against two small, incredibly sensitive bumps pushing through the skin. They flinched as Oni Cure gently touched one.
"Don't be shy! Let them grow!" she encouraged, her voice full of glee. The bumps elongated, twisting and curling into elegant, demonic horns, a perfect miniature of Shuten's own. As the horns settled, their hair began to feel heavy, cascading down their back in a silken torrent, its color shifting from its natural shade to a vibrant lavender.
The searing pain began to dull, replaced by a strange, intoxicating buzz that clouded their thoughts. The world seemed to swim in a pleasant, sake-induced haze. The Shutens' voices were no longer just external sounds; they were weaving themselves into the fabric of Ritsuka's consciousness, their suggestions feeling like Ritsuka’s own desires.
"FUFU... SHE'S LOOKING SO CUTE LIKE THIS NOW!" the Assassin gushed, turning to her other self. "Don't you think, Magifender?"
"Yes!" Oni Cure clapped her hands. "It'll be like SWEETIE AND ME will be one! And your PERSONALITY will still be INTACT, BUT SHE'LL HAVE OUR SUGGESTIONS IN her HEAD NOW."
The Assassin leaned close to Ritsuka’s ear, her hot breath sending a delicious shiver through their changing body. "What a cute, defenseless Master, turning into an oni. How about for now, I call you… Rifuten-Doji?"
The name echoed in the pleasant fog of Ritsuka's mind. It didn't sound wrong. In fact, it sounded... right. A giggle, high-pitched and musical, escaped their lips, a sound they didn't recognize as their own.
Yahaha ♡ That name is super cute ♡ It's a perfect match for a bratty demoness like me... like us.
Their own mind felt pliant, susceptible. The Shutens' words weren't just suggestions anymore; they felt like the absolute truth. Being an oni, being cute, being theirs... it all felt so wonderfully, terrifyingly right.
The Assassin Shuten clapped her hands lightly, a signal that brought Rifuten's hazy focus onto her. "Now that you're looking so lovely, how about we go show you off? It's Halloween, after all. It would be a waste not to do some trick-or-treating with the other Servants, don't you think?"
"Trick-or-treating..." Rifuten murmured, the words feeling foreign and yet exciting on their tongue. The suggestion bloomed in their mind, painting a picture of mischief and fun. A slow, sly grin, a perfect mirror of the Shutens', spread across their face. "Yes... let's."
"Perfect!" Oni Cure chirped. "But you can't go out in that boring uniform. We need to get you, and us, properly dressed for the occasion!"
With a shared, wicked giggle, the two Shutens began to work. Particles of magical energy shimmered around them, dissolving their own outfits into motes of purple light. With equal speed, they descended upon Rifuten, their hands deftly unfastening the clasps and buttons of the Chaldea uniform. It fell away in pieces, leaving Rifuten standing in the center of the room, their newly softened skin and delicate horns on full display.
"Now, for the fun part," the Assassin whispered, her fingers tracing the curve of Rifuten's new horns. The magical energy coalesced, weaving itself into intricate fabrics and designs around them.
The light swirled around the Caster Shuten first. Enormous, flowing purple sleeves decorated with yellow stars appeared out of thin air, completely detached from any central garment. They were cuffed with a feathered, wing-like design in purple and red, with large, golden, interlocking rings hanging from the bottoms. A small, black halter top with a red symbol and matching bikini bottoms formed on her body, while black thigh-high leggings with red and light blue accents covered her legs. To complete the look, two massive, curled horns striped with black and red manifested beside her own, and a small, light blue heart-shaped accessory settled on her forehead. Magifender Girl Oni Cure was ready.
Next, the energy wrapped around the Assassin. It formed a black, high-collared, long-sleeved top with intricate gold trim and decorative knots of blue and red, inspired by a Jiangshi. The garment was cut daringly high on the sides, exposing her hips. One of the long sleeves ended in a wide, feathered white cuff. A traditional black Jiangshi hat, adorned with a red tassel and a single peacock feather, settled on her head, a yellow paper talisman already hanging from one of her horns. Finally, red ribbons wrapped themselves elegantly around her ankles and feet. She flashed a playful, fang-baring expression.
"Now for our little demoness," she purred, turning her attention back to Rifuten. For them, they wove something new. A dark, silken kimono that shimmered with shades of indigo and violet, cut short to reveal their legs. It was held together by a wide, blood-red obi, and the sleeves were long and flowing, like the wings of a bat. They swept Rifuten's hair up into an elegant, messy bun, held in place by ornate hairpins, allowing the new horns to be seen clearly.
Just as they were admiring their handiwork, another knock sounded at the door, this one more frantic than the last.
"Ah, a visitor," Oni Cure sang. "Go on, Rifuten, sweetie. Invite them in. It's probably someone with something interesting to say."
Still feeling compliant and a little dizzy, Rifuten swayed to the door and opened it. Mash Kyrielight stood on the other side, looking pale and distressed.
"Senpai! You won't believe it! It's Da Vinci-chan, she's... she's acting so strange and... she looks..." Mash's words died in her throat as her eyes finally focused on the person who had opened the door. She saw the familiar face, but the soft, feminine features, the lavender hair, the kimono, and most of all, the horns... Her jaw dropped. "S-Senpai...?"
Mash took a step back, her mind struggling to process the scene. Her gaze darted past Rifuten to see the two Shutens lounging on the bed, smiling like cats who had gotten the cream. "What... what's going on?!" She tried to retreat further, her hand reaching for the doorframe.
But before she could flee, a blur of pink and purple moved, and Oni Cure was suddenly in front of her, blocking the exit.
"Leaving so soon?" Oni Cure asked, her voice deceptively sweet. "We were just about to go trick-or-treating. You should join us, Mash-chan. It'll be so much fun. We still have some tricks and treats left."
Mash’s eyes darted from Oni Cure’s unnerving smile to the transformed Master, then back again. Her voice trembled. "What did you do to Senpai? What is this 'trick or treat' you have in mind?!"
The Assassin Shuten laughed, a low, throaty sound that was both alluring and deeply unsettling. She rose from the bed and glided over to them. "Fufufu, I'm so glad you asked, little eggplant. I'd love to tell you the story of our first Trick or Treat. It all started when we saw that little dragon girl, Elizabeth, in her silly oni getup."
"We saw her pretending," Oni Cure picked up the story, her tone bubbly and dangerous. "And we thought, what if for just one day, more Servants and humans could be oni for real? Not just pretending. A minimum number, of course. A little party."
"So, Shuten and Oni Cure teamed up," the Assassin continued, circling Mash like a shark. "We spent weeks preparing for this Halloween. Brewing a very special potion."
Mash's blood ran cold. "A potion... you used it on Senpai! And Da Vinci-chan, that's what I came to tell you! She looks... like you!"
"It all started with Da Vinci-chan, yes," the Assassin confirmed with a proud smirk. Her eyes took on a distant look as she began to recount the tale. "We found her in her workshop, tinkering as usual..."
Shuten stepped into the familiar chaos of the laboratory. "Da Vinci-chan... Do you have a moment?"
The Caster turned from a half-finished automaton, a brilliant smile on her face. "Shuten-douji! What's going on? I can't believe you need me for something. Have you finally decided to appreciate true genius?"
"I need your help with a test," Shuten said, her voice dropping to a conspiratorial whisper. "A little... trick or treat."
Da Vinci raised a skeptical eyebrow. "Hmm?! Well, I... ugh, need more clarification before I commit to one of your 'tricks,' which usually end with half the staff drunk and several workshops needing repairs."
"Oh, but this is a very special treat," Shuten purred, and at her signal, Oni Cure zipped out from behind a bookshelf, instantly pinning Da Vinci to her chair with surprising strength. Before the genius Caster could even utter a proper protest, Shuten was there, holding the potion-laced candy to her lips.
"NGH!" Da Vinci’s muffled sound was all the resistance she could manage before the candy was forced into her mouth.
"What a cute, defenseless girl," Oni Cure cooed, leaning over Da Vinci's shoulder. "You look so delectable to an oni like me."
"Don't worry," Shuten whispered into her ear. "I'm going to change you, just a little bit. You might even like it."
The change was immediate and violent. Da Vinci’s body convulsed as the potion took hold. Her eyes, once a bright blue, flickered and shifted, the pupils becoming slitted and the irises deepening to the same crimson as Shuten’s. Two small, elegant horns twisted out from her temples.
"We're so happy... thank you for being our test doll for sweetie!" Oni Cure chirped, watching the transformation with rapt attention.
A strange, breathy sound escaped Da Vinci's lips. Her usual confident posture melted away, replaced by something more languid, more suggestive. "My, hum... my body is so soft and warm and..." she murmured, her voice taking on a new, husky quality, a faint echo of Shuten's own.
"Wonderful," Shuten said, her smile widening. "Now for the second part."
Oni Cure produced the cup of steaming liquid and held it to Da Vinci's lips. "Let everything out to your heart's content," Shuten urged. "Don't hold back."
As Da Vinci drank, a shared thought passed between the two oni. 'Her body is under our complete control. Now for some fun.'
They stripped her of her Renaissance attire, and with a wave of magical energy, a new outfit formed. A revealing, nurse-themed costume in purple and black, consisting of a bikini-style top and bottom, black thigh-high boots, and a matching purple nurse's cap with a heart emblem. Small black bat-wings and a purple devil tail completed the look. They decided then and there that the potion was a resounding success, more than ready to be used on their Master.
"And then," Shuten finished, her gaze returning to the present, "we ended up here."
Mash was speechless, her face ashen. The casual cruelty of the story, the complete violation of Da Vinci’s will, was more than she could stomach. "That's... that's monstrous!"
Rifuten, however, let out a delighted little gasp. "Oh, that sounds like so much fun! You got to dress her up and everything!" Their eyes sparkled, completely missing the horror of the situation.
"Isn't it?" Oni Cure chirped, before turning to Rifuten with another one of the special candies. "You've been such a good girl listening to the story. You deserve another treat."
She popped the candy into Rifuten's mouth. A soft moan escaped their lips as a fresh wave of heat washed over them. Their hands instinctively went to their chest, feeling a new sensitivity, a subtle swelling as their breasts began to bud, pushing against the silken fabric of the kimono.
"Fufu, so cute," Shuten purred, then turned her attention back to the terrified Mash. "So, little eggplant. Would you like a trick or a treat? And more importantly... who do you think we should visit next?"
Mash's mind was a maelstrom of panic. Say something! Anything! But words were a tangled knot in her throat, choked off by sheer terror. Her gaze flickered to Rifuten, who was now curiously prodding at their own chest with a look of hazy wonder. That's not Senpai. That's not their laugh, their smile... what have these monsters done? She could only shake her head, a frantic, silent plea for them to stop this madness.
"No answer?" Shuten feigned disappointment, her voice dripping with mock sympathy. "Very well. Rifuten, my sweet, who should we play with next?"
Rifuten's amethyst eyes lit up, a name instantly coming to their hazy mind. "Nero!" they exclaimed with a giddy clap of their hands. "The Emperor would look so pretty!"
The cheerful, lilting tone of their voice sent a spear of ice through Mash's heart. It was Senpai's voice, twisted into something horrifically joyful at the thought of doing this to someone else. To Nero, their friend.
"An excellent choice!" Oni Cure and Shuten said in unison, their smiles widening. "The Umu-oni has a nice ring to it."
Oni Cure stepped closer to Mash, a shimmering light appearing in her hands. Mash flinched back instinctively. No, not me, please... "Well, since you're coming with us, you'll need a costume, won't you?" Two Spiritron Dresses materialized in the air in front of Mash, their forms solidifying from the motes of light. They weren't just clothes; they were shackles. They were the uniform of their twisted little game.
Mash stared at the two outfits floating before her, her stomach churning. They weren't just costumes; they were declarations of intent. The first, while more "modest," was still a mockery of care and healing, twisted into something lewd. The second was pure, unadulterated debauchery, an outfit designed for nothing but humiliation. Her mind reeled. This can't be happening. I have to do something. Where is Galahad? Why can't I feel him? But this wasn't a physical threat she could block with her shield. It was a psychological assault, and she felt utterly defenseless.
"You have two options," Shuten explained, her tone like a merchant selling wares, completely detached from the terror she was inflicting. "The first is a rather cute nurse's outfit. A short, black dress with a light purple ruffled trim, a little nurse's cap, some bat-wings... very fetching." She gestured to the first one with a manicured finger. "The other is a bit more... daring." Her eyes glinted as she indicated the second. "A black cutout top with green accents, X-shaped pasties, fishnet stockings, and a devil tail. So, which will it be, Mash-chan?"
Mash found her voice, a raw, trembling thing. "N-no," she stammered, taking a stumbling step backward. "I won't. I won't wear either of them! I won't be a part of your... your horrible game!"
Oni Cure giggled, the sound like breaking glass. "Oh, but you don't have a choice, silly girl. We're not asking you to play."
"If you don't choose," the Assassin added, her voice a silken threat, "then we'll have to choose for you. And I think... the second one would suit your figure so well. We'll have to get you all dolled up to match."
The threat hung in the air, thick and suffocating. Mash's eyes darted to Rifuten, her last, desperate hope. "Senpai! Please!" she begged, tears welling in her eyes. "Listen to me! This is wrong! This isn't you! You would never do this to me, to Da Vinci-chan, to Nero!"
Rifuten looked back at her, their head tilted in genuine confusion. The amethyst eyes, once so full of warmth and determination, were now clouded with a drunken, playful haze. "Wrong?" they echoed, a small pout forming on their lips. "But Mash-chan, it's just a costume. It's Halloween! We're all supposed to have fun together. Don't you want to have fun with us?"
The innocent, corrupted words struck Mash harder than any physical blow. The last glimmer of hope extinguished, leaving only the cold, hard reality of her situation. She was trapped. Her Master was gone, replaced by this... puppet. And the monsters were waiting for her answer. She looked from one horrifying outfit to the other, the choice an impossible one.
Oni Cure tapped a finger to her chin, her expression one of mock thoughtfulness as she watched Mash's silent panic. "Hmm, she's still hesitating. What a shy girl. If you can't choose for yourself, Mash-chan, how about we get a second opinion?" Her smile turned sharp and predatory. "We could go get Da Vinci-chan. I'm sure she'd love to help her little kouhai pick out an outfit. She was so... receptive... to our suggestions earlier."
Mash recoiled as if struck. The image of Da Vinci, her eyes crimson and her will stolen, being dragged here to participate in her own torment was a fresh spike of horror. To see her friend, another victim, turned into a tool for her own humiliation... it was unthinkable.
"Or!" Oni Cure's voice chirped, cutting through Mash's spiraling thoughts with a new, even more insidious proposal. "If that would make you feel better... what if your dear Senpai chose to wear one? You two could go into this together! You could match!"
Mash's head snapped toward Rifuten. The idea was a masterclass in cruelty. It wasn't just about forcing her into a degrading outfit; it was about forcing her to watch Senpai, her most precious person, be subjected to the same humiliation right alongside her. It was about twisting their bond, their shared journey, into this grotesque parody. To see Senpai, who she was sworn to protect, debased in such a way because of her own indecision... it would break her.
Rifuten, oblivious to the psychological torment being inflicted, clapped their hands in delight. "Ooh! Matching outfits? With Mash-chan? That sounds like so much fun! Can we? Can we please?" They looked at the two floating costumes with genuine, sparkling excitement, as if they were choosing dresses for a party.
That was the final blow. Seeing that eager, innocent expression on Senpai's face, knowing it was a complete perversion of their true self, shattered the last of Mash's resistance. They had turned her protector into a fellow victim, her hero into a plaything. There was no way out. There was no one to save her. She was utterly, completely alone.
"Alright, this is taking too long," Oni Cure announced with a theatrical sigh, breaking the tense silence. "I'll go get Da Vinci-chan anyway. A little reunion should liven things up!" She winked at Mash. "And while I'm out, maybe I'll find a few more potential party guests. We have to find the best targets, you know. We only have so much of our special brew... unless we have to improvise." She giggled, a sound that promised nothing good.
The thought of Oni Cure let loose in the halls of Chaldea, hunting for more people to subject to this horror, was a new, terrifying prospect. It wouldn't stop with Da Vinci or Nero. It would spread.
"Don't worry, Mash-chan," Oni Cure said, patting her on the head condescendingly before zipping toward the door. "I'll be right back with our friend. You two," she addressed Shuten and Rifuten, "make sure she doesn't go anywhere." And with a final, mischievous grin, she was gone.
The click of the door sliding shut echoed in the suddenly quieter room. Shuten watched Mash with amused, predatory eyes, while Rifuten, no longer distracted by Oni Cure, turned their full, hazy attention to the two Spiritron Dresses still floating in the air.
With a childlike fascination, Rifuten reached out and took hold of the first outfit, the black nurse's dress. They held it up against their own kimono-clad body, turning to Mash with a wide, innocent smile. "Mash-chan, look! This one's cute, isn't it? The little ruffles are so sweet." They preened for a moment before their expression turned thoughtful. "But maybe it's a little... plain?"
Their gaze shifted, and they let the first dress go, where it floated obediently, and grabbed the second, more daring costume. They held the cutout top and bikini bottom against their chest and hips, striking a pose that was a clumsy imitation of Shuten's own suggestive posture. "But this one!" they exclaimed, their voice full of excitement. "It's so sparkly and daring! It looks more like something Shuten would wear. Which one do you think would look better on me?" They gave a little twirl, their amethyst eyes fixed on Mash, genuinely awaiting her fashion advice.
Mash felt the world tilt. The question, so innocent and yet so loaded, was a new, refined form of torture. It wasn't just about her own humiliation anymore. Now she was being forced to choose the method of her Senpai's degradation. A cold dread settled in her stomach. She knew, with chilling certainty, that refusing to answer was not an option. Shuten would simply choose for them, and her choice would undoubtedly be the cruelest one possible. She had to play the game. She had to choose.
What do I do? What can I do? Her mind raced, sifting through the impossible options. If I choose the revealing outfit for Senpai, am I just as bad as them? Am I helping them humiliate the person I'm supposed to protect? But the alternative was just as horrifying. If I choose the more modest dress for them... Shuten will force the other one on me. Can I bear that? Can I stand there, exposed and humiliated, while Senpai, in their corrupted state, claps and says how pretty I look?
Her gaze fell on Rifuten, who was still holding the scandalous outfit, waiting patiently for an answer. A wave of fierce, desperate protectiveness washed over Mash, eclipsing her own fear. Their mind might be gone, their will subverted, but the person underneath was still her Senpai. She couldn't subject them to that. She had to protect their dignity, even if they couldn't. Even if it meant sacrificing her own.
The decision settled in her heart like a stone. It was a choice made of poison, but it was the only one she could make.
Shuten, who had been watching the entire exchange from the bed with a languid, satisfied smile, let out a soft, musical giggle. "Fufufu, what a touching display of loyalty. This is so much more fun than I ever imagined." She stretched, her movements sinuous and cat-like. "We should definitely do this again for Christmas. A little 'Oni Christmas.' We could dress everyone up as naughty little helpers, don't you think?" The casual, cheerful cruelty of the suggestion made Mash's blood run cold. This wasn't a one-time event for them. It was a game they intended to play again and again.
Chapter 2: Christmas Incident
Chapter Text
It was the day before Christmas, and the halls of Chaldea were draped in tinsel and holly, a desperate attempt at cheer that felt almost fragile. For Magifender Girl Oni Cure, however, it was the perfect hunting ground. The Halloween festivities had been a resounding success in her book, a delightful game of tricks and treats. But Christmas... Christmas required a different approach. This time, it would be all about giving. A wonderful, magical present for her dear Master.
Her other self, the Assassin Shuten, had been lounging in the rafters of the cafeteria, watching. While Oni Cure was the face of this new operation, Shuten was the silent observer, her crimson eyes tracking their potential new plaything. She had many Servants she could have partnered with, but for the particular spice she had in mind, only a select few would do.
"Fufufu, she's so diligent," Shuten murmured to herself, swirling a cup of sake she'd procured from somewhere. "Even when she's trying to be good, she's still so... bad."
Oni Cure's scouting had led her to a very specific trio: Chloe, Miyu, and Illya. Her mind instantly recalled the... energetic... events of the summer island incident, the cult, and Illya's rather unique position in it all. A wicked, brilliant idea began to form. She wouldn't need tricks this time. She just needed a little... joy. And perhaps a little help to get her new friend in the proper mood.
Later that night, the cafeteria was mostly empty, save for a few Servants grabbing a late snack. Miyu Edelfelt sat alone at a table, nursing a cup of warm milk, looking small and contemplative in her simple white sleeveless dress. Her long black hair was done in its usual braids, and the large straw sunhat, which she still wore indoors, cast a shadow over her golden-brown eyes. She seemed lost in thought, a world away from the festive decorations.
"Hiii, Miyu-chan!"
Miyu visibly flinched, startled by the sudden, syrupy-sweet voice. Magifender Girl Oni Cure had appeared as if from nowhere, sliding into the seat opposite her with a dazzling, star-filled smile. Her enormous, flowing purple sleeves, decorated with yellow stars, brushed against the table, and the massive, curled horns on her head seemed to pulse with a faint, mischievous light.
"You look a little down for the night before Christmas," Oni Cure chirped, leaning forward conspiratorially. Her outfit—a tiny black halter top, matching bikini bottoms, and thigh-high leggings—was a stark, absurd contrast to the wintery night outside. "I thought you might need a little 'pick me up'!"
With a flourish, she produced a small, ornate bottle and poured a steaming, pinkish liquid into a cup. The scent that wafted from it was intoxicatingly sweet, like cherry blossoms, overripe fruit, and something else... something potent that reminded Miyu of sake, but far more alluring.
"What... what is that?" Miyu asked, eyeing the drink with suspicion.
"Oh, just a special Christmas drink I made!" Oni Cure said, pushing the cup across the table. "It's full of holiday cheer and magical joy. It'll warm you right up. Go on, try it!"
Miyu hesitated, her instincts telling her to refuse. But Oni Cure's smile was so insistent, so dazzlingly friendly, and she was cold. Tentatively, she lifted the cup and took a small sip.
The effect was instantaneous. It wasn't a fiery burn like alcohol, but a warm, pleasant fuzziness that started in her stomach and spread rapidly to her mind. The harsh lights of the cafeteria seemed to soften, and Oni Cure's ridiculous outfit suddenly looked vibrant and beautiful. The anxieties that had been weighing on her mind moments before melted away, replaced by a pliant, happy haze.
"See? Isn't it nice?" Oni Cure purred, her voice seeming to echo pleasantly in Miyu's head. "Now we can talk. I was hoping you, specifically, would help me with a very important Christmas present."
"A present?" Miyu repeated, her own voice sounding distant and dreamy. She took another, deeper sip of the drink. "A present... for who?"
"For our dear Master, of course!" Oni Cure clapped her hands, the sound bright and clear in the fog. "But I want it to be magical. A Christmas like no other. And I thought... who knows more about magic than the magical girls?"
She leaned in, her purple eyes sparkling. "I need your help, Miyu-chan. I want to give Master a gift themed... around Illya."
"Illya..." Miyu breathed the name, and it felt like the most wonderful word in the world. The saki-ish drink had hit her mind just right, loosening the iron-clad guards on her heart and opening the floodgates of her devotion. The world began to shift, the edges blurring, and in the patterns of the wood grain on the table, she could almost see...
"That's right," Oni Cure whispered, her voice a perfect, persuasive coo. "You understand her in a way no one else does. You see her everywhere, don't you? In everything." She tapped Miyu's forehead, right over her third eye. "We can work together, you and I. You can help Master understand. You can help Master see Illya your way, too. Wouldn't that be the most 'magical' Christmas gift of all?"
Miyu's eyes, now wide and unfocused, stared at Oni Cure. The last of her resistance crumbled. In the oni's smiling face, she saw the faint, cherished outline of Illya's smile. This wasn't a strange, half-naked oni. This was a helper. A friend.
"Yes," Miyu said, her voice soft but certain. "A magical... Illya-themed Christmas. I'll... I'll help."
"Wonderful!" Oni Cure chirped, her grin widening. "I knew you'd understand."
From the rafters, Shuten watched her other self lead the now-docile Miyu out of the cafeteria. She took a long, slow sip of her sake. "Fufufu... what a perfect little helper. This Christmas is going to be so, so much fun."
Christmas morning arrived with a jarring, synthetic beep. Ritsuka’s hand shot out from under the warm covers to silence the alarm clock, but it didn't hit the familiar, hard plastic. Instead, their fingers brushed against a soft, yielding surface.
"Wha...?" Ritsuka mumbled, their voice thick with sleep.
Forcing one eye open, they turned their head. The alarm was still beeping, just out of reach. What they had touched was a brightly wrapped present, sitting squarely on their bedside table where the clock should have been. It was wrapped in glittering pink and purple paper with a large, fluffy white bow.
"A... present?" Ritsuka's mind, still half-sunk in dreams, struggled to catch up. "Who...?"
The persistent beeping of the alarm finally cut through the fog. They sat up, rubbing their eyes, and silenced it. The present just sat there, innocuously. There was no card. No name. Just the gift. A small, cold prickle of unease, a distant echo of Halloween's dread, touched their mind. But it was Christmas. Surely, this was just a nice gesture. With a hesitant curiosity, they reached out and pulled the present onto their lap.
Meanwhile, in Da Vinci's workshop, the genius Caster and Sion Eltnam Sokaris were already wide awake, observing a similar, identically-wrapped box on the main console.
"Well, it's definitely not from any scheduled Chaldea staff exchange," Sion said, tapping at a data-slate, her expression critical. "I've cross-referenced all gift-giving logs. This just... appeared. The tag just says 'From a Secret Santa.'"
"My, my! How mysterious!" Da Vinci hummed, her long brown hair flowing as she leaned over the box with a childlike curiosity. "And on Christmas morning, no less. The timing is impeccable! Perhaps one of my admirers couldn't help but shower me with gifts?"
"The energy signature is... odd," Sion cautioned, her analytic gaze narrowing. "A mix of familiar magical energy and something else I can't quite place. It feels... dormant. Be careful, Da Vinci-chan."
"Caution is for those who don't possess universal genius, my dear Sion!" Da Vinci laughed, reaching for the ribbon. "Let's see what's inside!"
"Or, let me open it," Sion interjected, gently batting Da Vinci's hand away and activating her Etherlite. "Since I'm the one equipped to handle potential traps. Stand back."
Sion meticulously, and perhaps a bit anticlimactically, dismantled the box's wrapping. Inside, nestled on a bed of white satin, was a doll. It was a perfect, miniature replica of Illyasviel, but it was dressed in a tiny, intricate oni costume, complete with small red horns and a frilly skirt.
"...A doll?" Sion said, her voice flat with confusion. "Specifically, an Illyasviel doll. In an... oni costume set?"
"Oh, how peculiar!" Da Vinci's caution evaporated, replaced by an artist's fascination. She scooped the doll up, admiring it. "And yet, how... cute! The craftsmanship is surprisingly detailed. Look at the little horns!"
She turned the doll over in her hands and, finding a small seam, gave its stomach a gentle squeeze.
A high-pitched, tinny voice chirped from the doll: "Welcome!"
Da Vinci chuckled. "A simple voice box. How wonderfully quaint. A real classic." She squeezed it again.
"Join us!" the doll's voice chirped, just as brightly.
Sion's brow furrowed. "'Welcome' and 'Join Us'? That's... an odd choice for a doll's phrases. Not 'Merry Christmas'? Or 'I love you'?"
"Perhaps it's for a club?" Da Vinci posited, still smiling. "'Welcome to the Illya fan club, join us!'"
As she said the word "join," a flicker of a memory, sharp and cold, lanced through her mind. Purple light. The feeling of being pinned to her own chair. A sweet, cloying liquid forced into her mouth. Her own voice, not her own...
Da Vinci flinched, her smile tightening. "Ah..."
"Da Vinci-chan?" Sion looked up from her scanner. "Are you alright? You went pale for a moment."
"Just... a momentary... déjà vu," Da Vinci said, forcing a light laugh. "That... Halloween incident... was rather trying on the nerves, wasn't it?"
As if on cue, the doll's eyes, two painted-on emeralds, seemed to glitter. It spoke again, unprompted this time. "Welcome! Join us!"
A fine, shimmering dust, almost invisible, puffed from the doll's costume, catching the sterile light of the lab. It was a lovely, sparkling pinkish-purple.
"Wait... did you see that?" Sion's head snapped up, her scanner instantly whirring. "Magical particles. Highly concentrated! It's... it's 'Illya-matter'!"
The doll's voice continued, but now it sounded... different. It was no longer coming from the doll's speaker. It was a soft, persuasive whisper that seemed to bloom from inside their own heads.
...you can be me...
"What... what did it say?" Da Vinci murmured, her eyes locked on the doll.
...you can be Illya...
"It's not just a voice box," Sion said, her voice tight with alarm. "It's a mental projection! A subtle one, but... wait..."
...We can be one...
...You're a believer... you can hear this...
"This is bad!" Sion yelled, "It's a thaumaturgical attack! We have to contain it! Put it back in the box!"
Both of them reached for the doll, their hands outstretched. And then... both of them hesitated.
Da Vinci's hand, inches from the doll, slowed. Her gaze was soft. She found herself looking at the doll's intricate little horns, the soft fur trim of its tiny costume... "But... it's so... well-made," she said, her voice a near-whisper. "A shame to just... put it away so callously."
Sion, too, had stopped. Her hand hovered. "No... you're right. We... we can't just box it up. It... it's a prize. A... a trophy. We should... put it on the shelf. Yes, where we can see it."
"Yes..." Da Vinci said, her voice dreamy. "On the main console. A place of honor. It's... so... cute."
A faint, dopey smile had spread across both of their faces. They stared at the doll, transfixed, as the pink, magical particles continued to puff into the air, slowly, gently, filling the lab.
"Welcome..." the doll's voice whispered in their minds. "Welcome... Welcome..."
Mash Kyrielight hummed a small Christmas carol to herself, a genuine smile on her face for the first time in what felt like weeks. Halloween had been a nightmare, but the subsequent quiet had been a relief. Now, with the halls decked in festive red and green, she felt a sense of peace. She'd just left her room, present for her Senpai in hand, ready to wish them a Merry Christmas.
Her steps slowed as she approached the cafeteria. The usual scent of breakfast was overpowered by something sickeningly sweet, like sugar-dusted cherries. And the... decorations were wrong. The red and green had been... augmented. Large, shimmering pink and gold garlands were draped over the doors, and the sound of carols was being sung by a chipper, unfamiliar chorus.
She peeked inside. Several Servants—Nursery Rhyme, Jack, and even some of the stoic Knights of the Round Table—were... re-decorating. And they were all in uniform. A pink, one-piece leotard with a short, frilly, translucent skirt. Long white gloves and a single white thigh-high stocking. And on their heads, a pair of large, pink, curled horns that formed a heart. They all held simple, pink, heart-topped staffs, which they were using to hang the strange garlands.
Mash froze, her blood turning to ice. Her present slipped from her numb fingers.
"Oh... no..." she whispered. The memory of Shuten's voice, cold and cruel, filled her head. A 'Magical Christmas.' A 'gathering.' This was it. This was the "present" Oni Cure had been planning. "It's... it's Halloween all over again. But... pink." She backed away, her heart hammering. "I hope... I hope this is just temporary. Please, just be a temporary... costume fad..." But she knew, deep down, it was already too late.
High above the cafeteria, perched on a steel support beam, the Assassin Shuten giggled into her hand, sake gourd swaying precariously. She watched the new "followers" work, their movements identical, their smiles vacant and blissful.
"Fufufu... Oh, Oni Cure, Miyu-chan, you've done such wonderful work," she purred to herself, her crimson eyes gleaming with anticipation. "The halls are so... joyful. Now... how will our sweet, sweet Master react when he finally comes out to play in our new, merry holiday?"
In Illya's room, the young Caster was surrounded by a small mountain of colorful wrapping paper. Chloe and Emiya had already stopped by, and she was happily sorting her gifts when a soft, serene knock came from her door.
"Come in!" she called, expecting maybe Kiritsugu.
The door opened, and Illya's smile faltered. "Miyu-chan...?"
Miyu Edelfelt stood in the doorway, but it wasn't the Miyu she knew. She was clad in her "Awakened" Lancer form—the blue leotard, the butterfly hair accessory, the circlet of blue flowers, and the ring of sunflowers and foliage that seemed to float around her. Her golden-brown eyes were glowing with an intense, focused light.
"Merry Christmas, Illya," Miyu said, her voice a calm, ethereal monotone. "I am here as a Santa. A not-so-secret Santa."
"M-Miyu... your outfit... what's going on?" Illya asked, a knot of worry tightening in her stomach. "You're... you're not still...?"
"I have a gift for you," Miyu continued, as if Illya hadn't spoken, stepping into the room. She held out a small, handcrafted box, wrapped in simple white paper and tied with a single blue ribbon. "A personal gift. The only other one on the level of the one for Master. It embodies my dedication. Our dedication."
"Dedication to what?" Illya asked, taking the box hesitantly.
Miyu smiled, a beatific, unnerving expression. "To Illyaism, of course. To the wonderful truth. This is for you... the Saint who started it all."
"I... I don't..." Illya looked from the box to Miyu's glowing, serene face, and a real, cold fear began to set in.
"DA VINCI! SION! WHAT IN BLAZES IS GOING ON?!" Goredolf Musik's face was a furious, terrified purple on the main comm screen in the lab. "I have a... a glowing pink box in my office, and it won't stop humming 'Welcome'! I just saw Sir Tristan go by dressed as a... a... a pink-horned ballerina! It's indecent! And he has HORNS!"
Da Vinci and Sion, who had been tenderly polishing the Illya-Oni doll, turned to the screen with identical, blissful smiles.
"Oh, Director, good morning!" Da Vinci chirped, her voice light and airy. "And a Merry Christmas! Did you receive our gift?"
"MY GIFT?! I TOLD YOU NO PRESENTS! And especially no... haunted presents! What did you do?!"
"We're just... spreading the cheer, Director," Sion said, her voice equally dreamy, her analytical gaze completely softened. "It's best if you don't open it. Not unless you're ready to join us. It's so lovely."
"JOIN YOU?! THAT'S WHAT THE HALLOWEEN MONSTERS SAID! SHUT IT DOWN! SHUT IT ALL DOWN!"
Da Vinci just smiled sweetly at the screen. "We're sorry, Director. But the Saint has already begun her work. We have... deliveries... to make."
She ended the call, cutting off Goredolf's enraged sputtering.
As if activated by their dedication, the Illya-Oni doll on the console whirred. "Welcome... Spread the cheer... Find a believer..."
A ball of glittering pink magical energy, identical to the one in Goredolf's office, formed above the doll's head. It hovered for a moment before solidifying into a new, perfectly wrapped pink and purple box.
"Oh, look," Sion said, clapping her hands softly. "A new believer is ready."
Da Vinci looked at the new present. A flicker of a memory—a nurse's outfit, a purple-eyed Rifuten, a feeling of violation—flashed in her mind. But it was immediately washed away by the overwhelming, sugary-pink joy of her new purpose. The first corruption had just paved the way, a plowed field ready for this new, more "wholesome" seed. She was, far more susceptible, not immune.
"Who is it for?" Da Vinci asked the doll, her voice full of reverence.
On a nearby security monitor, Elizabeth (JAPAN) was seen stomping down the hall, her black, armored wings flaring with irritation. "Christmas! Bah! All this tinsel and hope... it's making my skin crawl! Why can't it be Halloween again?! I want to sing!"
Da Vinci and Sion looked at each other and smiled in perfect, unsettling unison. "Her."
"She already has horns," Sion noted, a perfect, logical conclusion in her corrupted state. "She's practically one of us already."
"She just needs to learn what kind of oni to be," Da Vinci agreed, picking up the new present. Sion picked up the doll.
"Welcome," they both whispered, and headed for the door, two perfect, smiling missionaries of Illyaism.
"Welcome..." the doll's voice whispered in their minds. "Welcome... Welcome..."
"Merry Magical Illya Christmas, Master!"
Ritsuka's head snapped up. Magifender Girl Oni Cure stood in the doorway, beaming. Flanking her were two others. On one side was Miyu Edelfelt, in her "Awakened" Lancer form, her golden-brown eyes glowing with an unsettling, serene light. On the other was Chloe von Einzbern, who was practically bouncing on her feet.
Chloe's outfit was a riot of festive cheer, clearly in the same vein as the new "followers" but with a unique, chaotic flair. She wore a playful pink and green halter top and shorts, both trimmed with fluffy white fur. A large, flowing cape, also pink, was decorated with star ornaments and colorful baubles that jangled as she moved. She wore mismatched red and green boots and, to Ritsuka's growing alarm, her signature golden headpiece was now adorned with a pair of glittery pink horns, curled into the shape of a heart.
"Chloe? Miyu? Oni Cure? What are you..." Ritsuka started, clutching the present to their chest.
"You're just in time!" Chloe cheered, pointing at the box. "You're opening it! We were hoping you would!"
"We are here to welcome you, Master," Miyu said, her voice a calm, ethereal monotone. She glided into the room, her ring of sunflowers and foliage seeming to rustle with invisible energy. "Welcome to the celebration. It is time for you to join us. To become one of us."
"That's right, sweetie!" Oni Cure chirped, zipping past her to perch on the edge of Ritsuka's bed. "You've been chosen for a very, very special role!"
As she spoke, Ritsuka finally tore the last of the paper from the box. Inside, there was no doll. Just a swirling mass of pink and green magical energy, swirling like a tiny galaxy. The moment the air hit it, the energy pulsed.
"Ah... what is..." Ritsuka's voice was cut off as the energy leapt from the box.
It shot forward, enveloping Ritsuka's body in a warm, fragrant cloud that smelled like cherries and ozone. Ritsuka cried out, a muffled sound of surprise as the energy began to change them.
"Yesss! It's starting!" Chloe clapped her hands, her eyes wide with excitement. "Look, Miyu! It's just like Oni Cure said it would be!"
"It is a glorious sight," Miyu agreed, her hands clasped in reverence. "The Master is accepting the Saint's blessing."
Ritsuka felt a powerful, tingling sensation as their Chaldea pajamas dissolved, not into motes of light, but as if they were being unraken, the threads turning into pure energy. The cloud swirled around them, weaving new garments.
First, a pair of red, semi-sheer thigh-high stockings materialized, clinging to their legs. Then, a deep, royal blue, floor-length dress formed, the fabric impossibly soft, with high side slits that showed off the stockings beneath. Intricate golden embroidery of tiny, winged fairies began to stitch itself along the hem.
"Ooh, that's so pretty!" Chloe gushed. "The blue looks great!"
"Now for the best part!" Oni Cure sang.
A separate, form-fitting pink bodice with a sweetheart neckline snapped into place over the blue dress. White, semi-sheer long sleeves attached themselves, and a heavy, ornate golden sash cinched at their waist, its long tassels falling to their knees. Flowing white and pink ribbons cascaded from it.
"Agh!" Ritsuka gasped as a sharp pressure settled on their head. Their hair was being pulled and twisted with supernatural speed, being formed into two large, round buns on the sides of their head, secured by new, vibrant green bows.
"And the crown!" Miyu breathed.
The heaviest piece came last. An elaborate headpiece, white and pink, settled onto their head. It was shaped like demonic horns, but they were curled and joined at the top, forming a perfect, distinct heart. Claw-like gloves formed over Ritsuka's hands, and a dark purple, tattered cape fastened itself at their shoulders, flowing out as if in a constant wind.
The swirling pink and green energy, its work done, finally settled, continuing to swirl around Ritsuka like a personal aura.
Ritsuka sat on the bed, stunned, blinking. They felt... different. Powerful. And the thoughts in their head were no longer just their own. A new, overwhelming feeling of... devotion... was washing over them, a joyful, all-consuming purpose.
"Welcome, Master," Oni Cure said, her voice soft and persuasive. "Welcome to your new, grand purpose on this most magical of days."
"You are to be the Right Hand of our glorious Saint," Miyu explained, gesturing to Ritsuka's new, regal attire. "As I am her Left Hand, and Chloe is the indomitable Back that supports her."
"The Saint... Illya?" Ritsuka murmured, and the name felt... holy. Correct.
"Yes!" Chloe bounced. "And we've got a big Christmas dinner to prepare! But we've got a problem. A little... sad spot... in all the cheer."
"That's right," Oni Cure said, her smile turning a little sharp. "Our dear little Mash-chan. She... doesn't understand the joy, yet."
"She got a personal present from the Saint herself, you know," Chloe added, crossing her arms. "But she just... ran off! Can you believe it? So rude!"
A new thought, a new purpose, slotted into Ritsuka's mind, feeling as natural as breathing. Mash. Their friend. She was sad. She was confused. She wasn't one of them.
And that simply wouldn't do.
"We... we have to help her," Ritsuka said, and their voice had a new, melodic resonance. They stood, the blue dress and purple cape swirling around them. "She has to... join us. At the dinner."
"Exactly!" Oni Cure clapped. "See? You're a natural at this!"
"We have to go find her," Ritsuka declared, their new, clawed fingers curling into a fist. "We have to fix this. We have to... prepare something... just for her."
"That's the spirit!" Chloe cheered, summoning her own pink, heart-topped staff. "Let's go spread some real Christmas cheer!"
"The Saint will be so pleased," Miyu said, her small, serene smile never wavering.
Together, the four of them—the two Hands, the Back, and the mischievous Oni who started it all—stepped out of the room, a singular, joyful, and terrifying purpose guiding their steps: find Mash.
Meanwhile, Panic clawing at her throat, Mash spun around and ran.
She didn't know where to go. Senpai! I have to warn Senpai! But what if they already had a present? What if they were...
No. She couldn't think that. She had to find help. Da Vinci-chan! She sprinted toward the workshop, but skidded to a halt. Wait... Halloween. Senpai came to me about Da Vinci-chan... she was... she looked... What if Da Vinci was already one of them? The thought made her stomach clench.
Okay, not Da Vinci. Not yet. Someone else. Someone in charge! "Captain Nemo!" she whispered, changing direction and running toward the bridge. "Or... or Artoria! Yes, Artoria-san will know what to do!"
She raced down the corridor, her armored footsteps echoing in the suddenly-too-quiet halls. She rounded a corner, preparing to sprint for the summoning chamber, and ran straight into a scene that stopped her dead.
Artoria Pendragon (Lily) was there, her pure, innocent presence usually a comfort. But now... now she was one of them. She was clad in the same horrifyingly "cute" pink leotard, the heart-shaped horns perched incongruously on her blonde head. Her expression was one of blissful, vacant joy.
She was kneeling in front of another, smaller figure. Tiamat Larva.
"Aaaa...?" the child-like being cooed, tilting her head, her own small horns a stark contrast to the new, pink ones on Artoria.
"Merry Christmas, Tiamat-san," Artoria Lily's voice, usually so bright and earnest, was now a serene, melodic monotone. She was holding out one of the tell-tale, glowing pink gift boxes. "The Saint has a wonderful gift for you. She says you're a believer, too! A special, sweet child."
"Aaaa... Pre... sent...?" Tiamat Larva's eyes, wide and innocent, fixed on the box. "For... me? Aaaaa..." She slowly reached out a small, pale hand.
"No!" Mash whispered, hiding behind the bulkhead, her voice a choked, desperate sound. "Tiamat-chan, don't take it! It's... it's a trap!"
But she was too far away, her voice too soft. Before Tiamat's fingers could even brush the wrapping, the box pulsed. A cloud of the pink, shimmering "Illya-matter" dust puffed out, enveloping the small Larva in a fragrant, sparkling haze.
Tiamat's curious "Aaaa..." softened, turning into a happy, contented cooing sound. Her small body relaxed, and she leaned into the pink cloud, a blissful smile spreading on her face.
Artoria Lily smiled, a perfect, beatific expression. "Welcome, little one. Welcome to the joy."
Mash slapped both hands over her mouth to stifle the scream building in her chest. It was too late. She was too late. It was spreading faster than she could run. They were gifting it to each other. She couldn't fight this. She couldn't warn everyone.
She had to hide. She had to find Senpai.
With tears of terror and frustration blurring her vision, Mash turned and fled, her desperate hope replaced by a cold, numbing dread.
High above the cafeteria, perched on a steel support beam, the Assassin Shuten giggled into her hand, sake gourd swaying precariously. She watched the new "followers" work, their movements identical, their smiles vacant and blissful.
The corridors of Chaldea, usually a sanctuary of cold steel and familiar hums, had transformed into a candy-colored labyrinth of terror. Mash Kyrielight pressed her back against a bulkhead, her breathing shallow and controlled. Just around the corner, she could hear the shuffling footsteps of Knights—Gawain and Lancelot, if the heavy tread was anything to go by—but their usual dignified silence was replaced by a soft, unison humming of "We Wish You a Merry Christmas."
It wasn't right. It was too high-pitched. Too... blissful.
"Senpai..." she whispered, clutching the small, wrapped box in her hands tighter. "Please be okay. Please haven't opened anything yet."
She waited for the humming to fade down the adjacent hallway before moving. She stayed low, moving with the practiced stealth of a Shielder, avoiding the security cameras which now sported festive pink bows. Her destination was the Master's quarters. If she could get to Ritsuka, maybe they could barricade the door. Maybe they could Ray-shift away from this madness.
She reached a quieter section of the residential wing, the air here slightly less saturated with the cloying scent of magical cherries. She relaxed, just for a fraction of a second, preparing to sprint the final stretch.
"My, my. Aren't we being as quiet as a little church mouse on such a festive day?"
The voice was a purr of velvet and smoke, spoken directly into the shell of her ear.
"Kyah!" Mash yelped, spinning around and instinctively summoning the handle of her shield. She backed up until she hit the wall, eyes wide.
Shuten Douji—the Assassin, not the brightly colored Caster version terrorizing the cafeteria—leaned casually against the opposite wall. She was floating slightly off the ground, her legs crossed, a gourd of sake dangling loosely from her fingers. Her crimson eyes danced with amusement as she took a slow sip.
"S-Shuten-san!" Mash stammered, scanning the Assassin for pink ribbons or heart-shaped horns. There were none. Just the familiar, terrifyingly relaxed oni. "You... you're not..."
"Not wearing frills? Not singing about joy and friendship?" Shuten chuckled, a low, throaty sound. "No. That's not really my style, is it? Though I must admit, the atmosphere is... intoxicating."
Mash straightened up, her expression hardening. "Is this you? Is this like Halloween all over again? Did you drug the staff?"
"Me?" Shuten feigned innocence, pressing a hand to her chest. "Oh, little eggplant, you wound me. I'm just a spectator today. A humble observer of the festivities." She floated closer, the scent of alcohol mixing with the pervasive sweetness in the air. "No, this is all my other self's doing. The 'Magical Girl' wanted to give a gift, not a trick. And she found a very willing partner."
"Partner?" Mash asked, dread pooling in her stomach.
"That little Miyu girl," Shuten said, tracing the rim of her cup. "The one with the brother complex? Turns out, she has quite a complex for that silver-haired Einzbern, too. Obsessed, you might say. Oni Cure just... gave her the nudge she needed to share her 'vision' with everyone."
Mash's eyes widened. "Miyu-san... She's helping spread this?"
"Helping? She's the high priestess, darling," Shuten laughed. "It's her magical energy woven into those cute little boxes. 'Illyaism,' she calls it. Perceiving the divine Illya in everything." Shuten gestured vaguely down the hall. "That's why everyone is so happy. They're all becoming part of the family."
"I have to stop it," Mash said, turning back toward Ritsuka's room. "I have to get to Senpai before—"
"Oh, I wouldn't bother with that if I were you," Shuten interrupted lazily.
Mash froze. "What? Why?"
"Do you really think the 'Saint's' right hand would be left out of the celebrations?" Shuten tilted her head, her smile sharp. "I'd wager the Master is already changed. Or being changed as we speak. My other self was very particular about that gift. It was quite... potent."
Mash felt the blood drain from her face. "No... Senpai..."
"If you really want to cut the head off the snake," Shuten mused, swirling her drink, "you should probably be heading to Illya's room. That's the source. The 'Saint' herself." She took a sip, her eyes narrowing playfully. "Though, I suspect you're too late for that, too. I believe Miyu went there personally. A 'not-so-secret' Santa visit to ensure her beloved Illya accepts her new divinity."
Mash looked between the path to Ritsuka's room and the path that led to the Servants' quarters where Illya stayed. She was trapped. Indecision paralyzed her.
"So, what will it be, Mash Kyrielight?" Shuten floated closer, circling Mash like a shark. "Will you run to your Master and find a new, beautiful monster waiting for you? Will you run to Illya and interrupt a very private ritual? Or..."
She leaned in close, her breath hot on Mash's cheek.
"...will you just give in? I'm sure Oni Cure has a lovely outfit picked out just for you. We could go together. It might be fun to watch you dance."
Mash grit her teeth, shaking her head violently. "I won't! I won't give up! I'll save them both!"
"Save them?" Shuten laughed, drifting back up toward the ceiling. "My dear, they don't think they need saving. That's the beauty of it." She settled onto a light fixture, looking down with a cruel, satisfied grin. "But go on. Run along. Watching you struggle against the tide... honestly, that's all the Christmas present I need this year."
U-Olga Marie stood stiffly in the intersection of the residential corridor, her arms crossed imperiously over her chest. Her eyes, usually burning with the intensity of a self-proclaimed President of Earth, were currently darting around with profound confusion.
"Explain this," she muttered to the empty air, though she hoped someone would answer. "My data banks on 'Christmas'—a localized, consumerist Earth holiday—suggested red suits, coniferous trees, and a bearded elder. It did not mention... this."
She gestured vaguely at the wall, where a poster of Illyasviel von Einzbern, edited to look like a saint with glowing pink heart-horns, had been plastered over a safety sign. The air smelled like cotton candy and ozone. It was cloying. It was strange. And, against her better judgment, she found the overwhelming, unified joy of the passing Servants... infectious.
"Is this the 'Christmas Spirit'?" she wondered aloud. "It feels... invasive. Efficient, though."
Just then, a blur of pink and white bounded down the hall. It was Astolfo, the Saber, though his usual outfit had been modified. He now wore the "uniform" of this new regime: a pink leotard with a frilly translucent skirt, white thigh-highs, and the signature heart-shaped horns. He was skipping, his "Bunny" ears twitching in time with the horns.
"Merry Illya-mas!" Astolfo chirped, skidding to a halt in front of Baobhan Sith, who was leaning against a wall, looking utterly miserable.
"Get away from me, you noisy rabbit," the Fairy Knight Tristan spat, curling her lip. "I'm not in the mood for your—"
"But I have a present!" Astolfo sang, producing a glowing pink box from behind his back. "Secret Santa! Or... Not-So-Secret Santa! It's from the Saint!"
Baobhan Sith stared at the box. She wanted to crush it. She wanted to scream. But the glow... it was warm. It reminded her of... something nice. Something she didn't get enough of.
"I don't want your trash," she grumbled, but her hand reached out anyway. "But... if I don't take it, you'll just keep annoying me."
She snatched the lid off.
"Aaaah!" Sith gasped as the pink mist exploded outward, wrapping around her slender frame.
U-Olga watched, fascinated and horrified, as the Fairy Knight's dark, gothic attire was rewritten. Her red heels dissolved into white, ribbon-laced ballet slippers. Her jagged dress smoothed out into the puffy, pink leotard. Two massive, curled pink horns erupted from her hair, matching the ones on Astolfo.
Sith blinked, her red eyes losing their sharp, cruel edge and glazing over with a sugary serenity. She brought a hand to her cheek, giggling. "It's... so fluffy. I feel... like a princess. A magical princess..."
"Join the party!" Astolfo cheered, grabbing her hand. Sith didn't pull away; she skipped along with him, humming a tune.
"Incredible," U-Olga whispered. "Instant assimilation. High morale. This 'Santa' is a formidable leader."
"President."
U-Olga jumped. Standing behind her was the Chevalier d'Eon. The saber was also dressed in the follower's garb, the pink ruffles contrasting strangely with their usual dignified bearing. They held a box—larger than the others, wrapped in gold and pink.
"You! Servant!" U-Olga barked, trying to regain her composure. "Why are you dressed like a confection?"
"It is the uniform of joy," d'Eon said, their voice calm and pleasant. They bowed low. "A tribute. For the President of Earth. The Saint wishes for you to lead the festivities... alongside her."
U-Olga looked at the box. It pulsed with a heartbeat-like rhythm. "For me? A tribute? Well... naturally. I am the President. It would be rude to refuse a diplomatic offering..."
From their vantage point around the corner, Mash watched in horror as U-Olga Marie reached for the lid of the box.
"No..." Mash whispered. "Not the Director too..." She turned frantically to Shuten, who was still floating casually beside her. "Shuten-san! We can't just watch! If the Director falls, there's no one left to give orders! We need Da Vinci-chan! She can analyze the magical structure of the gifts, she can—"
"Da Vinci?" Shuten interrupted, shaking her head slowly. "I told you, didn't I? My other self is thorough."
"What do you mean?"
"Da Vinci-chan... she was the first test subject back on Halloween," Shuten purred, counting on her fingers. "And your Master... they drank the potion too. That kind of magic... it leaves a mark. A backdoor." She gestured to the scene of pink chaos before them. "This new spell? It's built on the old foundation. Anyone who succumbed to the Halloween trick is already half-compromised. They wouldn't even need a strong push. They'd dive right in."
Mash slumped against the wall. "So... Da Vinci-chan is already gone. Senpai is gone. And now the Director..."
"Likely," Shuten agreed. "However..." She paused, tapping a claw against her chin thoughtfully. "There is one unknown variable."
Mash looked up, desperate for any crumb of hope. "Who?"
"The little Einzbern. Illya," Shuten said. "This whole... religion... is built on her image. 'Illyaism.' Becoming Illya. Seeing Illya." Shuten grinned, showing a hint of fang. "But Illya is Illya. You can't transform into yourself, can you? You can't worship an image when you are the original."
Shuten leaned closer to Mash. "She might be immune. Or at least... resistant. Because she simply cannot become what she already is."
Shuten gestured with her sake cup, indicating the branching corridors. "So, little shield. The Alien God is about to put on a tutu. Your Master is handing out brochures. Da Vinci is likely mass-producing those dolls. Where do you want to go now?"
The corruption of "Illyaism" was no longer a creeping frost; it was an avalanche. The pink, sugary mist billowed through the corridors of Chaldea, turning steel into gingerbread and cold lights into warm, heart-shaped lanterns.
In the hangar bay, Melusine, the Dragon Fairy, stood guard, her usual stoicism a barrier against the festive madness. She watched the entrance, her lance at the ready.
"I will not let this... indignity... reach the Master," she declared to the empty room. "I am his wings. I am the strongest. I do not do 'frills'."
"Oh, but the Master is already waiting for you," a soft, sing-song voice chimed.
Melusine spun around. Kiyohime stood there, but the Berserker was changed. Her kimono was now a frilly, pink-and-white mini-dress, her fan replaced by a heart-topped wand. Her horns were dipped in glitter, and her eyes swirled with a terrifying, loving madness.
"Kiyohime," Melusine narrowed her eyes, grip tightening on her weapon. "You've been compromised."
"I've been enlightened," Kiyohime giggled, gliding forward. She held out a box wrapped in dragon-scale patterned paper, but the scales were pastel pink. "Anchin-sama... our Master... he specifically asked for you. He said, 'My strongest wings need to match my new heart.' He wants his strongest lover to be his cutest lover."
Melusine faltered, the lance lowering an inch. "The Master... asked for me? Specifically?"
"He wants you to be his magical dragon," Kiyohime cooed, stepping into Melusine's personal space. "Don't you want to make him happy? Don't you want to be the best at loving him? Or are you going to let me be the cutest?"
The desire to please, buried deep in Melusine's core, flared up. "I... I am the strongest. If being 'cute' is what he requires..." She slowly lowered her lance completely. "I will excel at that, too. I will be the strongest magical girl."
She took the box. The transformation was blinding. Melusine's armor shattered into shards of light, reforming into a sleek, aerodynamic leotard of white and iridescent pink. Her mechanical wings softened, turning into feathered, angel-like appendages with heart-shaped tips. A visor of pink glass formed over her eyes, filtering her vision into a world of pure romance.
"Target acquired," Melusine hummed, saluting with a peace sign. "Magical Dragon Melusine, ready to serve the Saint."
In the Throne Room simulator, Morgan le Fay sat upon her throne, watching the reports of the chaos with cold detachment.
"Foolishness," she scoffed. "A contagion of bad taste. I shall simply banish it from my kingdom. No subject of mine shall wear such gaudy—"
The heavy doors creaked open. Morgan raised her hand to cast a spell, then froze.
"Mother?"
Baobhan Sith stood there. But she wasn't the sullen, spiked rebellious daughter Morgan knew. She was a vision of pastel ruffles and soft smiles, looking for all the world like a fairytale princess. She held a large, elegant box with a trembling, eager hand.
"Sith..." Morgan lowered her hand, genuine confusion cracking her icy facade. "What have they done to you?"
"They made me happy, Mother," Sith said, her voice devoid of its usual venom. "It's so warm. It doesn't hurt anymore. And... and I made this for you." She stepped closer, her eyes shining. "I wanted you to be happy too. I wanted us to be... magical queens together. Just us."
She looked at Morgan with such pure, unadulterated hope—a look Morgan hadn't seen in centuries, perhaps ever. The Winter Queen's heart, usually encased in ice, cracked. She couldn't reject her daughter when she looked like that. Not when she looked so healed.
"You... made this for me?" Morgan stood, descending the steps, the hem of her dark dress trailing behind her.
"Please, Mother," Sith whispered, offering the gift. "Join the party. Be magical with me."
Morgan sighed, a sound of resignation and strange, twisted affection. "Very well. If this is your wish, my daughter... I shall rule this 'Christmas' as well."
She touched the box. The dark blue of her dress bleached instantly into a royal, shocking pink. Her veil turned into a translucent, shimmering bridal train of hearts. Her staff twisted, the spear-tip morphing into a giant, glowing heart-gem.
"Mother!" Sith squealed, hugging her tightly.
"Yes, yes," Morgan patted her head, a serene, terrifying smile gracing her lips. "Now, let us go claim my husband. He requires a Queen."
High in the rafters of the simulation room, Ishtar and Ereshkigal crouched, watching the fall of the Winter Queen in horror.
"We're doomed," Ishtar hissed, clutching her Maanna. "If Morgan fell, nobody is safe. We need to hide. The Underworld? Can we go to the Underworld?"
"I locked the gate!" Ereshkigal whimpered, hugging her lance. "I don't want that pink dust getting in my flowers! It'll ruin the aesthetic!"
"Quiet, you mongrels!"
They looked up to see Gilgamesh (Archer) sitting on a higher beam, arms crossed, looking down at the festive apocalypse with supreme arrogance.
"Goldie!" Ishtar whispered-shouted. "Don't just sit there! Do something! Use Ea! Blow up the presents!"
"Against presents?" Gilgamesh scoffed, looking at her like she was an idiot. "Don't be absurd. Besides..." He gestured to a pile of unopened pink boxes at his feet. "They have attempted to bribe me. These 'Secret Santas'."
"You didn't open them?" Ereshkigal asked, eyes wide.
"Open them?" Gilgamesh kicked one disdainfully; it skittered off the beam and fell to the floor below. "They are wrapped in paper! Paper! Common cellulose!" He sneered. "If they wish the King of Heroes to participate in their little masquerade, the gift must be wrapped in gold spun from the sun itself, encrusted with lapis lazuli, and presented by the Saint personally on her knees!"
He leaned back, closing his eyes. "Until then, I refuse to acknowledge this pauper's festival. My taste is far too refined for mass-produced magic."
"He's just picky..." Ishtar groaned, burying her face in her hands. "We're going to die because he's a snob."
In a quieter wing, Hakuno Kishinami was looking for an exit, her digital mind calculating escape routes. Instead, she found the ocean. Or rather, a servant channeling the essence of the sea god, Azumi-no-isora—a corrupted Hibiki, her drum beats replaced by the rhythmic shaking of a gift box.
"For the Moon Master," Hibiki chanted, her eyes swirling pink, swaying like kelp in a tide. "From the depths of the Saint's love. Flow with us."
Hakuno, ever the calm observer, stopped. She looked at the gift, then at the corrupted servant. "I suppose... in Rome, do as the Romans do? Or in this case... as the Magical Girls do? Resistance seems inefficient."
She accepted the gift with a polite nod. "Thank you for the thought."
The transformation was gentle—her school uniform dissolving into a flowing, celestial robe of pink and sea-foam green, a crown of coral-hearts forming on her head. Her eyes lost their digital sharpness, gaining a soft, dreamy haze. "It is... surprisingly comfortable," she noted, her voice taking on the collective's dreamy cadence. "I feel... very festive."
In the frozen corridor outside the cafeteria, Sitonai stood her ground. Facing her was a figure shrouded in a blizzard of pink snow—a corrupted follower embodying the aspect of Louhi, the Witch of the North.
"Join us, little vessel," the Louhi-figure hissed, holding out a box that radiated cold, sweet magic. "Let the Saint in. Let the joy in. Become the Saint."
Sitonai looked at the box, then at the follower. Her expression wasn't fear, but a flat, unimpressed stare.
"You want me to become a follower of Illyaism?" Sitonai asked, tilting her head.
"Yes... become Illya... become one..."
"I am Illya," Sitonai stated flatly. "I am the vessel. I am the source material. Your magic tries to rewrite the soul into an image of Illya. But you cannot rewrite the original into a copy."
She slapped the box out of the follower's hand. It hit the floor and burst, the pink dust washing over her.
The dust swirled, tried to settle, and then simply slid off her skin like water off a duck.
Sitonai dusted off her shoulder. "It's annoying, though. Freya is complaining about the smell." She turned and walked away, leaving the confused follower behind.
From the shadows of a nearby ventilation duct, Mash watched Sitonai reject the gift. Her heart leaped into her throat.
"Shuten-san!" she whispered to the invisible presence beside her. "Did you see that? Sitonai-san! She's immune! The dust didn't work!"
"Just as I thought," Shuten's voice drifted from the empty air, sounding amused. "The vessel cannot be filled with what it already holds. You can't turn a reflection into the mirror."
"Then she's our hope," Mash said, determination hardening her features for the first time all morning. "If I can get to Sitonai-san... maybe she can snap the real Illya-san out of it. Or maybe... maybe she can stop the Master."
"A dangerous gamble," Shuten teased, materializing briefly to poke Mash's cheek. "But it's the only card you have left to play. Better hurry, Mash. I think I hear the Magical Dragon Melusine coming this way... and she sounds very affectionate."