Monstober 2025

鬼滅の刃 | Demon Slayer: Kimetsu no Yaiba (Anime) 鬼滅の刃 | Demon Slayer: Kimetsu no Yaiba (Manga)
F/F
F/M
Multi
Other
G
Monstober 2025
Characters
Shinazugawa Sanemi/Reader, Tomioka Giyuu, Kanroji Mitsuri, Kibutsuji Muzan, Kokushibou | Tsugikuni Michikatsu, Douma (Kimetsu no Yaiba), Daki | Ume (Kimetsu no Yaiba), Tsugikuni Yoriichi/Reader, Shinazugawa Genya/Reader, Kanroji Mitsuri/Reader, Kaigaku (Kimetsu no Yaiba)/Reader, Aizetsu (Kimetsu no Yaiba)/Reader, Iguro Obanai/Reader, Tsugikuni Yoriichi, Aizetsu (Kimetsu no Yaiba), Shinazugawa Genya, Shinazugawa Sanemi, Kaigaku (Kimetsu no Yaiba), Iguro Obanai, Uzui Tengen/Reader, Rengoku Kyoujurou/Reader, Hashibira Inosuke/Reader, Gyutaro (Kimetsu no Yaiba)/Reader, Tamayo (Kimetsu no Yaiba)/Reader, Douma (Kimetsu no Yaiba)/Reader, Murata (Kimetsu no Yaiba)/Reader, Daki | Ume (Kimetsu no Yaiba) & Reader, Ubume/reader(kimetsu no yaiba), Enmu (Kimetsu no Yaiba)/Reader, Kibutsuji Muzan/Reader, Ubuyashiki Kagaya/Reader, Kamanue (Kimetsu no Yaiba)/Reader, Hairou (Kimetsu no Yaiba)/Reader, Kokushibou | Tsugikuni Michikatsu/Reader, Sabito (Kimetsu no Yaiba)/Reader, Tomioka Giyuu/Reader, Kanzaki Aoi (Kimetsu no Yaiba)/Reader, Tsugikuni Akeno/Reader, Koinatsu (Kimetsu no Yaiba)/Reader, Akaza | Hakuji (Kimetsu no Yaiba)/Reader, Rengoku Shinjurou/Reader, Sekido (Kimetsu no Yaiba)/Reader, Uzui Tengen, Rengoku Kyoujurou, Gyutaro (Kimetsu no Yaiba), Hashibira Inosuke, Tamayo (Kimetsu no Yaiba), Murata (Kimetsu no Yaiba), Ubume (Kimetsu no Yaiba), Enmu (Kimetsu no Yaiba), Numa no Oni | Swamp Demon (Kimetsu no Yaiba), Ubuyashiki Kagaya, Kamanue (Kimetsu no Yaiba), Hairou (Kimetsu no Yaiba), Sabito (Kimetsu no Yaiba), Koinatsu (Kimetsu no Yaiba), Tsugikuni Akeno, Kanzaki Aoi (Kimetsu no Yaiba), Akaza | Hakuji (Kimetsu no Yaiba), Rengoku Shinjurou, Sekido (Kimetsu no Yaiba)
Summary
Decided to do another monster filled month because why not? Also it's just regular monsters this time. I'm gonna try to do different monsters from what I did last year. So enjoy!
All Chapters Forward

Day 17 Demon

 

 

 

"Let's summon a demon!"

 

A thunderstorm rolled across the sky that night. The sun was just setting over the horizon with the last few rays of daylight disappearing but it was hard to tell when the dark storm clouds took over the sky and claimed them as their own. Thunder shaking the lanes of the windows and lightning sounded off like an angry whip from whatever deity was angrily stomping around the clouded skies, lighting up the sky and city below for nothing but a brief second.

 

It would've been absolutely dark if you hadn't lit up a few candles inside the comfy room and placed them on the table to light up the room. The warm light comforting against the scary night sky that just appeared as the last few daylights were chased away. The candlelight was pretty but you might be asking yourself one question. Why are you using candles to light up the room when you can just turn on the light switch on the wall or use a flashlight like a normal person?

 

Well because it wasn't your idea. It was your friend's.

 

If it were up to you, your bedroom light would've been on in an instant and you four wouldn't be sitting here in the dark. But as another thunder clap shook the sky outside, her face had scrunched up into a mischievous grin wide enough to let the other three ladies around her know that she had come up with a devious idea. It started when of your friends said that they were bored during the usual sleep over activities and so you suggested watching a scary movie instead!

 

"How about The Death Book?"

 

"What's it about?"

 

"It's about this girl who finds this blank diary and everything she writes in it becomes true! It turns out the diary is possessed by a demon who becomes obsessed with her and grants her wishes with horrible twists!"

 

That's when your most devious friend gotten that look before hijacking the convo. "I have a better idea! Y/n, you have any candles?"

 

"Only scented candles. Why?"

 

"That'll work! Go get them all and we'll do something that's actually thrilling!"

 

You had no idea what she was talking about but decided to humor her and go get them and matches she asked for. You had a few scented candles collecting up space in your closet, most were Christmas gifts you were just planning on regifting that year anyways since you never really used them. But you were curious about what your friend was up too so you grabbed up all the bars, the different scents making your nose snort, and brought them out to everyone watching you take them out of your closet and plopping them down on your bed. Your friend then proceeded to grab a glass jar containing a 'holiday sugar cookie' scented white candle, lit it, and then got up to turn off the lights and ask you to close the curtains.

 

Oh! She wanted to do the classic ghost story telling in the dark game! Nope. As soon as you turned around and you along with your other two friends looked at her, the statement left her mouth.

 

"Let's summon a demon!"

 

The three of you stared at her and her smile lit up by the scented candle, a nice scent of sugar cookies in the air. The only sounds being the thunder still rumbling outside. Eventually one of you broke the weird silence.

 

"You mean like...Use a ouija board? That's something everyone does at sleepovers-"

 

"No! I meant actually summon a demon!," she corrected excitedly clenching a fist!

 

"Uh..Have you lost your dam mind?"

 

"Oh come on! We all know that ghosts and stuff don't exist anyways!" She waved a hand dismissively. "We've tried using a ouija board since we were ten but nothing ever happened so why not try taking it up a notch!"

 

"Because it sounds like a waste of time." You deadpanned raising a brow. "Why go through all the effort to do something when we already KNOW that it's just stupid Hollywood stuff?"

 

"For the thrill of it!" You three looked at each other. Two of you having bored looks while the third looked worried. "Come on! Just this once! And if nothing happens I'll pay for two pizzas from that pizza place we all like!"

 

"...Throw in those chicken tenders and a couple sodas and you have a deal," your bored friend bluntly stated.

 

"DEAL!"

 

"I don't know.." Your friend that looked worried frowned. "This is how a bunch of horror stories start. What if something really happens?"

 

"PSH. It won't. If nothing happened when we used a ouija board then we got nothing to worry about!"

 

"And you just magically happen to know how to summon a demon how?"

 

"Not just a demon!" Her hand pointed up as she grinned. "A Yokai!!"

 

"A yo-..What?"

 

"A Yokai! Or oni if you prefer to call it that instead! It's a Japanese spirit!"

 

"We know what that is! And you happen to know that how?"

 

"During my culture studies at school I was studying the local folklore and stumbled onto an old legend of the area! They say that a monster used to roam the lands and strike down evil people every until a shrine was put up for him. It's still there now! I visited it during a school trip!" She explained excitedly. "I did an interview with the caretaker for my extra credit report and it turns out his family's descendants of the shrine maidens that used to be there!"

 

"That's good and all but that still doesn't answer my question."

 

Your friend groaned loudly and slumped her shoulders with an eye roll. "He said the shrine maidens used to have a symbiotic relationship with the specific oni. They'd perform a ritual once a year on a new moon or full moon to summon him and leave him really good offerings. If he liked it enough he might grant you something in return!"

 

"And he told you how to summon this thing?"

 

"Yeah because he didn't believe in it. I don't either since ghosts and goblins only exist in books and movies. But what's the harm? If nothing happens I'm buying everyone food and we can have a good laugh if we do happen to summon something we might get a wish granted! Whaddya say?"

 

There was more silence from you three until your bored friend sighed and rolled her eyes from where she sat. "Fine I guess. Sounds like a win win situation. And I wouldn't mind getting an A on my next math exam."

 

You sighed. "Alright. Let's just get this over with."

 

"That's the spirit! But first thing's first!.. Does anyone know if it's a new or full moon tonight?"

 

Your nervous friend, who still looked nervous, had to pull out her phone and look it up online. The glow of the screen making her face light up in the dark as the thunder still rang out and the first few raindrops began hitting the roof of your home.

 

"Full moon b-b-but does it count if the storm is blocking out the sky?"

 

"He only told me it has to be a full of new moon, not that you had to see the moon. We're also gonna need thirteen white candles to represent the sacred number of his, something red to draw the symbols in, and an offering from each of us that has some kind of connection to our wishes!" Her eyes lit up in excitement. "Let's try it out!"

 

If it got you free food and your rowdiest friend to be quiet, then you weren't going to complain. So you four got to work. A friend found an extra red lipstick when she dug out her bag and like you said before, you had a bunch of scented candles you weren't using....but that begs the question.

 

"Does scented candles even count?" You gazed down at two white scented candles with the scents labeled 'fresh morning snow' and 'shortbread blast'.

 

"He just said that the candles had to be white, not that they couldn't be scented."

 

"Yeah. But there's another problem. I only have twelve white candles. .." Your eyes looked around the mini candle collection. The others were different colors like the red one that smelt like cinnamon and the purplish-black one labeled 'midnight lilacs'. Eventually you found a glimmer of white in the limited darkness with only your phone to see, and pulled out a candle that was half white half brown labeled 'chocolate and vanilla delight'. "I got a brown and white one. Does that count?"

 

"We're gonna have to make due with it. Well just put the white half facing the center and maybe that'll help."

 

Well if that's all you had then you four really were going to have to make due with what you had on hand. One friend helped you cleared up space in your room at least a yard and a half clear, while your devious friend drew red lipstick marks onto your floor and the fourth began placing the candles in a circle around her lighting them up as she went until both stepped away and you four were left looking down at the circle of thirteen candles and three symbols in the center of them. Lightning clashed outside behind the curtains barely lighting up the room but you managed to make out three words written in Japanese kanji in red lipstick.

 

Muzan. Progenitor. And King.

 

You didn't know what that meant but it was ominous in your eyes. The room smelt far too heavy with the pretty scents of sugar cookies, vanilla, daisies, and a few other scents. It was overwhelming and one of you snorted from it all.

 

"Dam. It smells like someone spilt the entire isle of Fabreath from Wallace-Market in here." She waved a hand before pinching her nose and turning to her. "So what now?"

 

"Now we put down an offering related to what we want to wish for? Like if you wanted to wish for a million dollars you put down like some rare collector coins or something! Just look around and see what you got!"

 

While the others looked through their bags, you mindlessly searched around the room for something meaningless you could just throw meaninglessly into the circle. Your eyes gazed over at your jewelry box...and you shrugged. Why not? You had a pair of thick hooped silver earrings your uncle gave you for your birthday last year. They were even real silver, just cheap copper ones painted to look silver. You never wore them anyways so they'd be perfect for this. You opened up the lid narrowing your eyes into a squint. Despite the light of your phone, it was hard to see in the dark. Your hand moved things around inside the box. Old necklaces and things jingling until you saw them. Ah! There they were! Right next to your great grandparents' wedding rings. Now THOSE were actually worth a lot. Real gold and studded with real diamonds. You inherited them box along with their old jewelry box but that didn't matter right now. You wanted the useless tacky earrings next to them. Even now most of the shiny silver paint had peeled off revealing the cheap copper hoops underneath.

 

"C'mon Y/n! Hurry up! I want that pizza as soon as possible!"

 

You looked around mindlessly just reaching in and grabbing two round things into your hand. "Coming!"

 

"What did you grab?" Her brow rose as you just rolled your eyes.

 

"Just some old jewelry. What about you?"

 

She held up an ink stone. Probably got it from her school bag. "I was gonna use it for an art project but since I want an A for my exam and I have to write on the test, it was a good enough match."

 

"Sounds like a good start."

 

Your other two friends pulled out a book on rare poetry and a small bag of store bought mochi candy. ...Strange offering but you guessed it was the only thing that they could find. Your friend instructed you all placed the offerings on the strange words in Japanese and stepped back without a second thought to look at them....And you four stood there in your pajamas with nothing but the candles to light up the darkness and the rain still pounding at your rooftop.

 

Silence other than the storm rang out and you four looked around the room exchanging looks sometimes.

 

".....Is that it?"

 

"I told you it was a waste of time! Let's just get some food now. I'm starving!"

 

"Wait! I forgot about the last important step!" She held up her hands as your mutual grumpy and hungry friend turned to go flip on the light switch. "I need to chant the incantation and then we have to say what we want!"

 

Her arms folded. "Well get on with it! I'm hungry and this is really not fun!"

 

"Alright, alright! Let me try to remember what the guy told me!"

 

She stood there staring at the mess of lit candles and lipstick smeared kanji scrunching her brows in deep thought. You and your grumpy friend exchanged mirrored deadpanned looks before she cleared her throat and held her arms out.

 

"Full moon on the rise. New moon hides from eyes. Abyss of darkness conquering the skies! We summon, summon him from the ground. To our circle lit and round. Oh one who walks the path of light, we come once more to ask you to chase away evils blight! Come from slumber, to seek out what we offer! Great one of good and light, we ask for you to once more walk the night!"

 

Her voice shouted out loud enough that you were sure you'd be getting a complaint from the neighbors tomorrow morning. As she finished her chant, a lightning bolt struck out temporarily lighting up the sky outside as the rain poured out...As you all waited looking around more.

 

"Would you look at that? Nothing happened again. NOW can we get food?"

 

"Wait! We didn't say what we wanted yet!," she protested to her, "The wish is a part of the ritual so let's complete it ok?!" Your friend groaned but she quickly excitedly exclaimed. "I wish my mom would finally give me the secrets to famous udon recipe so I can start selling it myself!"

 

"Um..." You nervous friend cautiously and worriedly looked around the dark room. "C-Can I m-meet my favorite author please? O-Only if that's ok! I'm fine if nothing happens really!"

 

"Oh what the hell. I want an A on my next exam."

 

...All three looked at you expectantly. "What?"

 

"Say something, Y/n."

 

"Like what?"

 

"I don't know. What did you put down?"

 

You shrugged. "Some cheap jewelry I don't want honestly."

 

"OOOH. Wish for something good then! Oh! Oh! I see you always sitting by yourself! Ask him to get you a boyfriend?," you friend teased making you laugh.

 

"Really? We summon a Yokai just for me to ask him for a boyfriend? If he was real, he'd probably think I was crazy."

 

"Well it doesn't have to be a boyfriend. You can ask for a sign of who you're meant to be with." That devious smile returned again. "Y'know that caretaker guy told me a lot of maidens would pay the shrine maidens to do rituals and summon the onis as offered brides in exchange for good fortune for their villages. Why don't you ask him to put a ring on it? You'd be the first person to be get a real life monster boyfriend. All the monster lovers on the Internet would be so jealous."

 

"Plus you're beautiful," your grumpy friend added also with a teasing grin. "You made home coming and prom queen in highschool!"

 

You laughed again. "Looks aren't everything." You could barely contain the giggles. You then rolled your eyes sarcastically. "But sure." Your hands clasped together and pressed against your chest as you spoke. "Oh great Oni please hear my pleas for your heart!" Even your nervous friend giggled along now as you dramatically fell to your knees. "Bind our blood in ceremony and let me share your name." A hand outstretched to no one as you fake acted out processing your love to an invisible imaginary person. "Under the stars of the heavens, I solemnly swear, that this hand will always be kind and never cruel. That my voice will only speak truth. That this life is now forever yours." The outstretched hand pretended to take the imaginary person's hand. "Now as yours is mine."

 

A loud snort went off as one of your friends fell back on your bed where she sat giggling out the cheesy lines you were making up on the fly.

 

"Bind our souls to infinity and I will promise you love and devotion through sickness and health and beyond the realms of death." You continued to speak remembering some lines from a rom com chick flick you saw last night. "I will love you in all your forms now and forever. Through several lifetimes and back." Your voice was low and smooth now speaking it like you meant it with pride. "From now to infinity. Unyielding. Untainted. Undeniable. With this voice I promise you my love and heart. With this offering, I ask you to be mine!" You then bowed your forehead to the floor as everyone continued to giggle loudly.

 

You all continued to laugh and laugh and laugh as you finally broke into laughs again too and sat back up-

 

And then all the candles went out at the same time.

 

Pitch black immediately enveloped the room and at once all laughs ceased. Nothing but silence rang out other than the rain and thunder and occasional strike of lightning. You four stayed silent as you all say there in the dark before your friend became grumpy again.

 

"Ok. Haha. Very funny, Y/n. Now we can't see shit!"

 

"That..w-wasnt me," you stuttered out staring at the floor in front of you silently and wide eyed.

 

"Sure it wasn't. You're literally kneeling in front of them!"

 

"I don't have the ability to blow out right giant candles at once! Besides some of them were out of my reached! I'd have to crawl over! It wasn't me!"

 

"Well it's not me! I'm standing up!"

 

"It wasn't me!" "I'm sitting all the way over here on the bed."

 

Silence fell Once Again as you all sat there.

 

"....It must've just been a draft! There's no such thing as ghosts and demons! Get the light! I'm tired of this game now!"

 

Someone was heard stumbling and shuffling around in the dark before you heard hands patting along the wall and then a serious of clicks as someone tried turning on the lights. "It won't turn on!"

 

"No one panic!" Someone finally turned on the flashlight on their phone and lit up the room. "The storm just cut out the power supply. Let's just get some food and call it a night!"

 

"Wait! The offerings!"

 

The light shines towards the middle of the circle. One bag of mochi candy, an ink stone, and a book still laid there. Where was your earrings? You pushed the book aside and froze as you realized that it wasn't a cheap pair of earrings that greeted you..but one beautiful gold ring.

 

"My great grandmother's ring!" You quickly snatched it up safely into your hands in horror. "I-I must've grabbed them by mistake!" Wait. You remembered feeling two hoops in your hands. "My great grandfather's ring!" Quickly you pushed aside everything else and was horrified to discover that it was gone. "IT'S MISSING!!"

 

"Calm down. It must've rolled away or someone accidentally kicked it in the dark. It's still around here."

 

"Yeah. And so is everything else. I CALLED IT! I TOLD you it wasn't gonna work! Now order the food!"

 

"B-But my ring!"

 

"It's too dark to look with the power out. Let's just wait until it's day time and then we'll look around. Ok?"

 

"I-...*sigh* Alright."

 

"GREAT! Now let's eat. And don't forget the chicken and drinks!"

 

You went to go stand up-

 

Creak!

 

A shriek left your friends and yourself as the floor boards beneath your feet began to shake and quake under your feet. The boards shuttered to life joining the storm's tags as they rattled around everything in your room including all of you. Books and knickknacks fell off shelves and your desk hitting the floors scattering about like it was a full earthquake of in your room. Windows shook and the bedroom door rattled around as one of your friends fell over onto their side hitting the continued moving boards hard. Until all at once it stopped.

 

And then all the candles lit back up at once.

 

You blinked at the sudden light. But froze as your eyes were met with feet and sandals. Ever so slowly your terrified eyes looked up. Pupils shrinking as eyes widening at the sight of black hakama pants. A haori coat hung loosely around a thin but muscular frame. And finally your eyes met a face. A thin lipped line of a mouth met you and red slitted eyes looked down upon you. Shoulder length black hair.hung from his head and two horns protruded from his forehead. The silence carried on as you both still stared as your friends looked on horrified, and then a clawed hand held up a shiny golden band.

 

"I accept."

 

"W-Who are you?!"

 

"I go by many names. My enemies know me as Death. Your people as a god. My family as Muzan Kibutsuji." Those beautiful eyes widened even more, especially when a hand reached out to tilt her chin back up to him, the feeling of his claws making her shiver under his careful grasp. "You as Husband. I have decided that I accept this coupling."

 

Your hyperventilating lungs breathed- GASPED for air. Lips. Trembled. Body shook. Tears welding up. "I-I.. Can't accept."

 

"I'm afraid you have no choice but to honor those vows because now-..Not even death will do us part." 

 

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