|| 𝐮𝐩𝐩𝐞𝐫 𝐦𝐨𝐨𝐧 𝐳𝐞𝐫𝐨 ||

♧︎︎︎

|| 𝐭𝐡𝐞 𝐜𝐡𝐚𝐦𝐛𝐞𝐫 𝐨𝐟 𝐬𝐞𝐜𝐫𝐞𝐭𝐬 ||
050

ꨄ︎

y/n tsugikuni

"come with me."

those were the words upper moon zero muttered to me after the experiment, it's been a month ever since i was captured and learnt the truth of my existence. i don't know when i turned into a demon, upper moon zero didn't mention anything about the age that i turned into one. then again, not like i'm aware that i'm a demon myself because i never showed any kind of signs of wanting to devour a human, nor perishing from the sun.

following upper moon zero in her quarters, i live with her inside this huge domain of hers. unlike the other one that is filled with rooms and doors, and basically an empty-open space, this one is filled with house furniture. i learned about her endless domain, she can create any type of domain with just the creativity forming in her brain. she told me, she built this domain for me to stay in whenever we're not in the laboratory where muzan and the upper moon zero experiments on me.

they wanted to find out the source of my being, the reason as to why i could live without devouring a human nor perishing from the sun. although i'm the same as nezuko, they couldn't careless about her because i'm the one who was captured, and as muzan said, i'm interesting.

"penny for your thoughts?" i heard upper moon zero said while opening the sliding door to her chambers, i collected my thoughts and didn't bother replying because not like she'll listen anyway. 

she glance at me for a moment before stepping aside, ushering me inside which i did. i look around her chambers for the first time, she never once let me visit her chambers and not like i invited her to mine. there is no point in being friendly with a demon, but if it's the only way for me to seize the opportunity of escape then it wouldn't hurt to try.

"have a sit, i would like to talk to you." said upper moon zero with a small smile on her face, she sat on a couch and across from her is a small table and a couch similar to the one she sat on.

staring reluctant with her friendly demeanor, i ended up sitting across from her, and a bead of sweat threatening to fall on the corners of my forehead. i don't know what is her purpose for inviting me in her room, but something about this makes me uncomfortable.

"i am not one to share my past, but i'll tell you because you deserve to know." she said as she grab hold of the tea cup on the table, it contains a bloody red color which i'm assuming is blood that came from a human being.

"you see, my name is mitsuki takahashi." 

F L A S H B A C K

mitsuki takahashi

a bead of sweat started dripping from my forehead as i wipe it with my long-sleeve cloth that is filled with dirt and stains. it's been eight hours ever since i started working in this small factory that creates charcoal, and a few more minutes then i'm free from this hell and i'll get may payment for this day. 

as i focused my attention of packing the charcoals, my thoughts started to wander to my younger baby sister. a huge smile plastered on my face as i thought of her reaction into seeing me after eight hours of being gone, m/n is my younger sister who is thirteen years younger than me. she suddenly got conceived, and mama died from giving birth to her.

unlike how papa was welcoming when mama gave birth to me, papa absolutely hates m/n with all his heart. hate is a strong word, but he uses it to express his hatred towards my younger sister. papa loves mama so much that he couldn't let her go, thus he ended up bottling all the hatred he has for m/n until two months after she was born did papa snapped and almost killed her. 

after that i fended for the both of us, i started working in this factory to earn little money to buy food that will be enough for a month of our survival. sometimes i'd go on a day without eating anything because m/n tends to ask for milk for every hour, and i don't have enough money to spend more on milk, so every time i buy food, i mainly focus on the milk and instead bought at least two to three pieces of bread that would last for a week or two. 

papa works for himself, he earns big money because he performs accompanied by an instrument, the mandolin. since our town isn't that much popular, nor does it have talented people, or somewhat you call "prodigies". papa would always get called by wealthy families, and to perform whenever they have this huge occasion. but that money earned by him is only spent to himself, and he couldn't care less about me and m/n.

although we live in the same house, papa wouldn't bother looking at me nor m/n. he told me that he would only fend for me if i decided to abandon m/n in the streets which i couldn't do. how can he hate his own child just because his wife died after giving birth? it is only natural for women to die when giving birth during this period because of the lack of supplies and knowledge. 

shaking the dark thoughts that started circulating around my mind, i heard someone calling out my name. turning around, i found the head of the factory with a small smile on his face as he handed me the money to buy food for me and my sister. my eyes glowed upon seeing the envelope, a huge smile plastered on my face as i quickly thanked the head before running my way out of the factory and towards the town market. 

an hour have pass, and on my hand is a plastic filled with bread and powdered milk. staring upon the sun that is setting, the beautiful orange-red color that fills the whole view as it slowly transition from the sun, to the moon. soft humming escaped from my lips, this melody that i have been humming is a composition that i did randomly, i plan on using this melody to help my baby sister fall asleep with ease. 

i reached my house in a matter of time, without knocking on the door. i grab the spare key in my pocket before opening the door, i didn't bother announcing my presence because papa wouldn't respond anyway. i heard from his assistant that he doesn't have any events to attend today, so he's home all alone with the maids, i just hope he didn't meddle with them when they were taking care of m/n.

"l-lady mitsuki." i heard a soft voice calling for me, turning my head to the side, i saw one of the maids who have tears escaping her eyes as she ushered me to come in the room she's staying in.

a frown formed on my face as i went closer to her. she pulled me inside the room, and quickly shut it lightly to not make an echoing sound. she faced me with her guilt expression, her lips trembling in fear as she bit onto it hardly. 

"lady m/n, she's missing." mumbled the maid with a hint of guilt lacing in her tone. 

my eyes widened from what she said, i drop the plastic filled with food on the floor causing a huge booming sound to echo in the room. i opened my mouth to say something but nothing came out of it, a frown plastered on my face as i tried envisioning the person who took her.

"your father, he started yelling and throwing things in his room. then one thing lead to another, he went to your sister's room. all the maids were there, and we couldn't do a thing because he ended up hurting all of us, he took your sister somewhere away from home and he came back an hour ago with a smile on his face. i don't know where he left her, i-i'm sorry." said the maid as she bursted into tears, i could feel the regret and guilt she's expressing because she couldn't do anything to stop my papa from taking my baby sister.

"m/n is only nine months, and the weather is cold, if he left her somewhere outside and arrived an hour ago. are you telling me you didn't went out to search for her?" i demanded as i grab the collar of her uniform, pulling her near my face as she shook her head. 

"you and the other maids that i trusted the most, didn't do anything at all." i mumbled, my voice shaking in anger as my fists tightened.

"you piece of shits deserve to die, and burn in hell." i yelled before headbutting the maid causing her to yelp in pain. 

without another word, i rushed outside the house and started my search for m/n. i have hope that she's alive somewhere, but since it's freezing cold there is a possibility that she'll end up dying from freezing to death. if only i knew this would happen, then i wouldn't have left her in that house.

searching for thirty minutes and there is no signs of her. i felt my breath shortening from all the running, and the tears that started forming in the corners of my eyes as i let out small sobs while continuing my search for her, how many hours have she been in the snow? how many hours have she been alone in the freezing cold weather? my eyes glistened from the blur, i couldn't see properly from the tears that escaped my eyes as i wandered around the forest, trying to search for the familiar cloth that's wrapped on my sister before i left for work.

"M/N!" i yelled out, the desperation coming to me as the adrenalines running through my body kept growing. 

"M/N WHERE ARE YOU!" i shouted once more, hoping that she'd recognize my voice and possibly respond by crying out loud.

and just like that, a familiar cry caught my attention as i spun around from my position before running towards the direction where the cries could be heard. by the distance is my baby sister wrapped in a thin layered cloth, her face filled with snow that's been dropping from the sky, and her skin color started turning gray.

a sob escaped my lips as i held onto her dearly, i felt her cold body against my heating one, the feeling of her being unresponsive is scaring me to death. she just cried a moment ago, then suddenly she stopped and became unresponsive. 

i felt my feet running towards the person who showed us kindness, the person who would give me money to buy food for me and m/n. he doesn't know much about my situation at home because i wouldn't tell him, but he said that i could come running to him for help if i needed something.

upon arriving by his doorstep, i panted for a moment before knocking on the door furiously. hoping that he isn't around town, tending to patients that needed help with their illnesses. 

"a moment." i heard the voice of kamado-san. 

the door knob started twitching, and the door is slammed open with kamado-san staring curiously at me. a look of confusion on his face as he saw me and my baby sister in front of his doorstep in such a snowy day.

"my, what do we have here. come in, hurry." he said, pushing me inside as he close the door lightly.

"my sister's been out in the cold, please tend to her." i hurriedly said as he patted my head, trying to calm my nerves down.

"i know you're panicking and all, but remain calm and i'll tend to her. sit by the firewood, and after this we'll have a talk." he said before entering a room that i assumed would be his operating room, i've been to his house a couple of times and whenever a patient comes to see him, he'll let them enter that room. 

an hour have pass ever since he entered the room with my baby sister. suddenly the door made a creaking noise, lifting my head up i notice kamado-san with a gentle smile on his face as he nodded his head, confirming that my sister is indeed alright. my lips trembled, and the fear from my body soon left and is replace with relief. 

"your sister is now safe from harm, now would you mind telling me what happened." kamado-san said with a gentle tone in his voice.

i nodded my head and started telling him the story of how papa hates m/n, while i'm telling him the story. he prepared a hot chocolate drink for me, and a yummy cake with raspberry filling. he listened to my story attentively, with a huge understanding in his heart, and by the time i finished my story i was wrapped around his fatherly embrace as he comforted me with sweet words.

"i've known you ever since you were little mitsuki, and i'm willing to help you in this situation of yours. so what do you say about living with me, i'll tend for you and your younger sister for as long as you want." said kamado-san.

and that was the start of our newly built family, akio kamado, mitsuki takahashi, and m/n takahashi. for those ten years that passed, m/n grew into a fine young kid who took after mama, her beautiful burgundy-hair, burgundy-eyes, and smooth s/c skin. for some unknown reason, m/n does not look like me, nor papa, nor mama. i thought it was weird, but then it might only be an illness just like what papa akio mentioned from before. for those ten years, i grew to call kamado-san as papa akio. he raise me and my younger sister and i am in debt to him. 

i thought my life is complete, i found myself with a loving family, a father who tends to his children and expresses his love in so many ways, and a younger sister that welcomes me at home and shares to me everything she did for the whole day. 

but that was until i learned the secret. 

"m/n is my daughter." 

i heard papa akio talking to another person in his office. that whole sentence alone made me freeze in my spot, those words ringing in my ear as it echoed all throughout my body. the only thing that keeps me sane right now is because i didn't want him knowing that i heard what he said.

papa akio is m/n's biological father. all this time, he's been sheltering us and giving us love because his daughter is my younger sister? is this the whole reason of him taking care of me? is this why he's friendly and loving towards me, because i'm m/n's older sister and i took good care of her? is this his way of paying for his debts because i raised m/n?

so many thoughts circulated from my brain, the fear, the anguish, the hatred. mix emotions started bottling in my body until i could no longer breathe and think properly. that night where i learned the truth, is the night where everything changes, the once whole happy family demeanor broke apart and the coldness lingers everywhere in the house. then everything went cold, numb, and silent.

as the time pass, my sister met a man by the name kenji tsugikuni. he is eight years older than her, and five years younger than me. i know that he's a man that only have eyes for my sister, but i couldn't help but feel jealous whenever i see the both of them together, their smiling faces, their happy demeanor, oh how i wanted all of that all to myself.

two years of their relationship, kenji proposed to m/n which she gladly accepted. my blood boiled, my eyes twitched from irritation. how can kenji love someone like m/n? a disgusting being that is conceived with an affair because my mother's a whore who couldn't keep her hands to herself. 

that time, i was drowning from anger and hatred that a man with plum red eyes appeared out of nowhere and gave me an offer to live for decades and in exchange i can devour anyone who i want to devour, and i mean anyone. 

five years passed ever since i became a demon, and here i stood in front of akio's home. i heard he became sickly and couldn't move anymore. he is now an old man who can't defend himself from harm, and that's why i came here to finish him off. 

blood dripping from my arms as i left a hole in akio's stomach. a huge smile plastered on my face, a chuckle leaving my mouth as i stared at akio's fallen body on the ground while staring at me with no emotions. but suddenly he gave me a gentle smile, and everything around me turned quiet as if time had stopped.

"i'm sorry mitsuki for ruining your family. your mother has always been in love with me, we were sweethearts until your father came and swept her away."

"i didn't mean to conceive a child with her, we were both drunk that night, we laughed the pain away because we didn't end up together just like how we dreamt of." 

"i know i've made a huge mistake, but thank you for allowing me to be a father for you and m/n for those ten years that i've treasured."

"and i have no regrets of dying by the hands of my sweet daughter."

those were the last words he said, then everything went silent and his heart beat drops.

that night i cried in agony and pain, the man who i grew up seeing as a father is killed by his own daughter, me. i may not be his biological daughter, but he seen me as one and he raised me to be someone who's carefree, loving, and caring but after hearing his secret that night. i didn't bother asking for his explanation and instead turned my back against him and my sister. 

"rest well, papa." i mumbled as i rested his head on my lap.

a few more years passed by and my sister finally conceived a child and  was given the name y/n kamado. i learned from kenji that he didn't want y/n carrying his last name because it'll only put her into grieve danger. he didn't want muzan-sama to come and slay his last remaining family.

the night where kenji is away from home, that was the day where i strike. i heard the familiar melody that i've been playing to m/n since she was an infant, the lullaby that i'll hum whenever she sleeps during the night. she sang it to her daughter with passion and love, and she mentioned about me and wondered where i was.

biting my lips, i hurriedly came in the house and struck m/n. her blood escaping her body as she squinted her eyes to look at me, without another word, i struck her daughter as well but this time with the intent of turning her into a demon. 

"m-mitsuki?"

"i-is that y-you?" 

i heard m/n's  soft tone of voice as she tried to speak with blood flowing from her mouth, turning my head i stared at her laying form on the ground, and just like papa akio, she gave me a gentle smile.

"after all those years, i've finally found you."  i heard her said, her voice slowly fainting as i look at the other direction, somewhere i couldn't see her pitiful face.

"have you met my daughter? her name is y/n." m/n said, a frown forming on my face as i tried hiding the watery fluid that is about to escape my eyes.

"i know you didn't mean it, and i still forgive you even after i die. but please if my daughter manages to survive. watch over her for me."

those were the last words m/n muttered to me. 

i stared emotionless at y/n who looks like she's no longer breathing, perhaps my blood isn't enough to turn someone into a demon. other than that, i went back to the headquarters with a heavy heart, but nonetheless gave my most menacing smile as i reported to muzan-sama the news of me slaying kenji's wife and daughter.

E N D  O F  F L A S H B A C K

y/n tsugikuni

no words escaped my lips, my body remained numb as i tried processing upper moon zero's past. i felt my lips trembling, as tears started forming in the corner of my eyes. 

"i killed your father too." upper moon zero, or rather mitsuki said with no emotions as she stared at my trembling body.

all those years of mourning over my dead father, of promising myself to protect my younger cousins from these filthy demons, only to find out that i'm one of them and that two of them are my relatives. 

"why did you kill them, why did you-

"because of hatred and pain, do not be like