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Language:
English
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Published:
2025-04-16
Completed:
2025-07-12
Words:
55,983
Chapters:
29/29
Comments:
5
Kudos:
25
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11
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878

Kimetsu Magica (a Puella Magi Madoka Magica AU of Demon Slayer: Kimetsu no Yaiba)

Summary:

In an alternate universe where Demons take the place of Witches and their slayers are Puella Magi, Nezuko Kamado becomes a half-Demon after Muzan forces her into a life-altering transformation. No longer a normal human girl any longer, Nezuko struggles to balance her true self with her new magical girl identity. Her elder brother, Tanjirou, is determined to protect his sister from the sinister pull of Muzan’s influence. As they battle powerful Demons and face the cruel system of Puer Magi, the siblings must confront their shared destiny, the power of love, and the price of survival in a world torn between demons and magic.
A Puella Magi Madoka Magica AU set in the Demon Slayer world. Spoilers for both series will be present. Periodically and non-scheduled updates.

Chapter 1: Prologue: White Rabbit

Chapter Text

Prologue: White Rabbit

 Her first thought is that rabbits almost never have tails this long, nor did they have such red eyes. Her second thought was that decidedly, this creature was not a rabbit. It looked more like a white cat, with a strange, uncanny smile upon its face.
 Nezuko knelt down as best as she could without pressing her kimono into the snow, grateful that Rokuta had gone down for a nap indoors after seeing Tanjirou off. With the weight off her back gone, she had set off to find mountain herbs to eat with their dinner.
 Which led to this strange encounter, gazing down at the creature who stared back, barely blinking at all. 
The dark clouds loomed, sunlight barely coming out to illuminate the bright snow fields and dark trees. 
 
 “Where did you come from, little guy?” Nezuko finally spoke, extending a soft hand out to the creature. It didn’t sniff her like a dog might. It just came close and ran its head under her fingers, back arching and curling much like a pleased cat. 
 “I come from far away. But I came looking specifically for you, Kamado Nezuko.
 The girl yelped, falling flat on her butt in the snow. The chill of the slush immediately penetrated her clothes, and she groaned, slowly getting back up to brush the snow off her clothes.
 “You… You can talk. Are you a yokai of some kind?” Her mind wandered back to her grandmother’s stories of demons and strange spirits, of the yokai who inhabited the world between worlds. 
 “No, I am not a yokai,” The creature responded without moving his lips, his voice filling her head. “My name is Kyubey. I am a scouter for Puer Magi.
 Nezuko swallowed. “Puer… Magi?” All of this felt like some odd dream. 
 “In your language, they would be called Magical Children. They are incredibly powerful protectors of your world, fighting battles you cannot see as a normal human. They’re very special. And I believe you have great potential as a Puella Magi, Nezuko.” Kyubey’s large tail swished, ears flicking.
 “Me? Special?” The human responded quizzically. Something in her gut churned, a warning that what was happening was wrong. She wasn’t safe.
 “What… What does one have to do to become a… Puella Magi?” The words still felt foreign in her mouth. Nezuko found herself frozen, staring down at the creature, as if looking away would break the dream.
 “It’s quite simple,” Kyubey continued. “You simply make a contract with me. In return, you’ll be granted one miracle, any wish you desire. You will gain magical powers with which to defeat Demons.
 That sick feeling in her gut grew stronger. Nezuko swallowed thickly, breath trembling as it fogged around her rosy lips. 
 “Demons?”
 “Yes,” Kyubey nodded once, strange bunny ear-like appendages bouncing. “They live on the boundaries of human perception, feeding upon their souls and bodies, should they wander into a Demon’s Labyrinth. Only Puer Magi can defeat them, and gain rewards in return.
 
Somehow, it felt like there was something that Kyubey was leaving out. Nezuko wasn’t even sure how she knew this, but she could feel it in her gut. Her heart was thudding so loud in her chest she felt sick.
 “So, what do you say, Nezuko?” Kyubey peered up at her, eyes squinting like a broad smile. “Is there something you wish for so desperately, you’d do anything for it to come true? That you would fight for it?
 There was. Deep down, she knew it. She wanted to be enough for her family. To be strong and capable, never faltering. If she could hold tight onto their future with her own hands, to ensure her siblings got plenty to eat and felt love their whole lives… She would give up her own happiness for their sake.
 And yet, the idea of making a contract now on her own felt like a betrayal. She always insisted upon fighting battles with her siblings’ support. They were a family. They endured their trials together.
 Another thought came to mind. Tanjirou would know how to properly formulate the wish. He would know what to say to make sure it went right, that they all could be happy. 
 If she knew for certain her family could be saved, she would fight these Demons. Right now, she was too uncertain to feel comfortable making that leap.

 “I’m not ready yet, Kyubey. I’m sorry.” Finally, Nezuko responded, her hands clasped together and squeezing nervously. “I want to talk to my big brother when he gets home. Make sure I’m making the right choice. I want to be sure my wish is right, you know?”
 “I understand completely.” Kyubey nodded. Relief bloomed within the girl’s chest for a moment.
 “I will be around. If you decide you are ready to contract, call me. I’ll be there.” Turning around, he took delicate, feather-light steps upon the snow. Nary a paw print was left behind. 
 “I’ll be waiting, Kamado Nezuko.” He said over his shoulder, and with a sudden hum of light, he was gone.
 
 Nezuko stared at the spot where the strange creature had stood, her breathing uneven, loud in her ears. Overhead, snow began to lightly fall from the dark clouds. She was running out of time.
 “Oh no, I’ll be late–” Hissed under her breath, she grabbed the woven basket with the day’s meager findings, before picking her way as quick as she could manage down the slopes towards home.

 A few moments later, a heavy footstep crunched. A man in pure white stood amongst the plucked herbs, his snazzy business shoes the only flush of color. Well, besides his strange red eyes.
 The man hummed to himself a moment, blue-hued fingers tracing the spot where Kyubey had stood a few minutes before. Already, his tracks had become almost completely covered by snow. But the man could see them, and he smiled.
 “I guess I better get there before the Incubator rat does.” With a confident smile, he glided down the slopes, right towards the Kamado household as the world grew dark.