Kimetsu no Yaiba does not belong to me but to Koyoharu Gotōge ... I only do this for fun and hobby
Warning: This is an AU. I think there is a slight Out of Character, don't blame me! I am new to fandom.
There are also changes with the manga canon.
5 years ago.
On the slopes of a mountain where winter covers those landscapes, the white snow is adorned with reddish nuances as a result of a cruel scenario in a humble house that is currently desolate since, if you look inside the home, we will find a terrifying scene: 5 lifeless bodies scattered, where red is adorned on walls and floor. Outside is a man in elegant clothing, black hair, and plum red eyes trying to hang a young man with burgundy black hair, dark red eyes, a scar on his forehead, hanafuda earrings, and a peculiar green and black plaid haori .
Tanjiro Kamado doesn't know how on earth things changed for the worse. On the morning of that day he went out to sell coal in order to earn some money for his family and then when he returned very late at night he found that his family was cruelly annihilated, and the worst thing is that the unknown man tries hang him to end his life, he didn't understand anything.
Hearing a feminine scream, he barely directs his gaze to observe that someone gets up despite the severity of his injuries to get to where they were. That young female with dark pinkish eyes, long black hair, wearing a white yukata that is adorned with blood from her wounds.
"Nez ... uko" The boy whispers between tears and pain despite the fact that inside, it is relieved that there was at least one survivor of his massacred family. The man loosens his grip to observe the situation.
"Please ... Don't kill my brother. Forgive your life, if you want something in return ... take my life" Tearfully, Nezuko bows as he pleads for his brother's freedom in exchange for his sacrifice.
"N ... no ... DON'T DO IT! ... If so ... you better take mine and save hers" Scared, Tanjiro yells at him since he prefers his sister to live than his own existence.
"Brother not! .. arg ..."
"You have to live Nezuko."
"I will not do it! I would change mine for you to live."
While both argue, the man delights. He never thought that these people try to exchange their lives for the sake of another regardless of whether in the end they would seem.
"It's interesting. One wants the other to live and vice versa ... it is the first time I see this. Boy answer me, where did you get those earrings?"
"My father ... gave it to me. It is something that ... is in the family ... from past generations ... and is inherited from father ... to eldest son" He answers with a broken voice.
"Do you know if any of them were slayers?"
"Slayers? ... The Kamados have ... been burners of coal ... for a long time" At that answer, the smile of his captor disturbed him a little.
"Wow ... so they don't know the truth of those earrings as well as that annoying organization. It would be interesting if ..."
"Please don't kill my brother. I will give my life if it is to save him" The female Kamado continues to beg in tears.
"Brothers ... well, I will not finish them to your relief" Before they smile hopefully, the young feel like sharp claws dig into their throats causing muffled screams.
"Instead, you will join me. What that man did in his will end here when the conversion is complete, accept my blood, my cells ... from now on, you will serve me for all eternity."
Before falling into unconsciousness due to the burning and pain that began to flood their bodies as a result of that blood that was injected by force, they listen to what would be their sentence from now on.
"It's time for your rebirth, my demons."
His body feels heavy, when opening his eyes it is difficult to focus since his mind is empty and groggy, he tries to say something but his throat is very dry that it even burns and his limbs are stiff as well as a rare sensation of emptiness expands in all his being and did not know what it was.
"I see that you are assimilating" He finds it difficult to identify the source of the voice, he feels how they take his face and forces him to open his mouth.
"Drink this, you will soon regain consciousness " Sense? To drink? What is he drinking? The taste of that liquid was metallic that disgusted him but at the same time it was sweet ... wait, since when did a liquid with an iron-like flavor also be sweet? He wanted to complain but his voice never came out and he could not move. With that one thought, unconsciousness succumbs to his person again.
He did not know how long he was sleeping, he only knew that when he woke up, his senses were at another level and a strange sensation stirred in his chest.
"I see you woke up. Your sister is waiting for you" Sister? He has a sister? His mind remains fuzzy as well as his memories and thoughts.
"I have ... a sister?" His faint and raspy voice resonates, the black-haired man sighs and then take one of the fingers ... wait, those are claws?.
Before he said anything, something sharp pierced a part of his skull. That man manipulated to bury with his own finger / claw in his head while a moan is heard on his person and images come quickly as a whirlwind causing a nuisance in his head.
"Did you remember?" When you ask that question, someone shows up in the room where the young man is. A girl with long black hair with orange highlights on the tips, pink eyes with a cat-like pupil, sharp claws and dressed in a simple white yukata.
"Tanjiro ... you woke up," says the smiling girl, appreciating her fangs.
"Tanjiro ... Is that my name?" He mumbles confusedly.
"Apparently he is in the same situation that you had when you woke up." That man talks to the female, who makes a gesture of concern.
"I see," She whispers with some disappointment.
"If you want, you can help him. I have business to do."
"Will you delay? I therefore..."
"Is something wrong?" That behavior on her part caused him some intrigue.
"Nothing ... Have a nice day" She says in a respectful way while making a simple bow. The man with long black hair and plum red eyes nods silently and before leaving, gives the brothers one last look to finally get rid of the place. Far from where he was, the thought of the enigmatic adult focuses on that pair of siblings and their reactions due to the transformation.
"I have a feeling that these children will do something good for my benefit."
The newly awakened Tanjiro silently watches that young woman who claims to be his sister, studying her physique in order to fit in with what he saw in his memories, however a whimper comes from his person. The tiredness and the strange sensation inside him bothers him too much.
"Does something hurt?" Nezuko asks worriedly.
"My head ... hurts" whispers something hurt in what with his claws massages his head in order to relieve that annoying pain.
"1 week ago I was like this" Surprisingly, the girl hugs him and whispers to calm him down.
"What happened?" He asks, trying to fight not to sleep.
"We were saved. That man saved our lives from a tragedy."
"Tragedy? " Nezuko sighs to start narrating.
"That man is called Muzan Kibutsuji. He found us badly injured since a wild creature attacked us, killing our family and seriously injuring us, the possibility of saving us with medical attention was impossible, so the only way to avoid our end was to become demons "
"I thought they were non-existent."
"But now it's what we are.
"Do we eat humans?"
"I cannot. Mr. Kibutsuji gave me some human flesh and blood but I couldn't tolerate it, so I'm still hungry."
"So the strange feeling that I have was hungry ..."
"Do you want to try it?" Nodding, the girl takes her brother to eat some of his food and that unfortunately, Tanjiro did not tolerate both blood and human flesh. They had to wait for their savior to return to tell what had happened and for this man, it was strange that newly converted demons could not tolerate the only food source.
"I see ... it's rare that you cannot accept humans as food" Muzan comments more to himself when he returned to his room 1 week later
"Hunger is greater Lord Kibutsuji. How will we support ourselves if we can't eat?" At Nezuko's question, the adult sighs as he cuts his palms.
"While looking for an alternative, drink my blood. I will not allow my children to go through hardships" Hearing that, the brothers are surprised.
"Children? Are we your children?" Asks both at the same time.
"Yes, you are the only ones who may deserve special treatment under my care."
Because for that man with a cold and dead heart, the direct and indirect contact of these children generated heat even if only microscopic. He had thought hard about it in that short time since he met them although at first he thought it would be a mere game since those brats are his puppets, however during the 2 months he spent time with them as they adapted to the new life , strange sensations expand which surprised him ... be it a smile, a show of affection or seeing them happy, provoked what for a time he thought he had lost: Emotions. Not even the human family that usurped their enemies as a form of distraction, was capable of generating those emotions, nothing comparing with the mere presence of Tanjiro and Nezuko ... those were supposed to be their puppets, they should not be attached as it would be weakness in his person, a being who seeks perfection 100%.
Muzan watches for seconds the young people doze, or rather, he admires that scene although to himself it was insignificant that being demons they had to be doing that very human act. Is it an effect of not eating humans? He had to find a solution to that dilemma if he wants to avoid giving more of his blood to them. He sighs to rest from his reading and peeks at the sleepers resting on his legs, Tanjiro being on his right and Nezuko on his left, studying and differentiating some details of the current appearance versus the old one they had: The boy kept the characteristics like his hair and eyes, being an addition that black / red gradient mark in the form of flames that runs from his forehead on the right side of his face to his chest although, it still bothers his that he uses those obnoxious earrings.
"I don't know why but ... these earrings are very special to me" That was Tanjiro's answer when Muzan asked why keep using those accessories. No matter how many attempts he made, it was impossible for the boy to put those things aside so he opted for the option of ignoring them.
And as for Nezuko, her hair became spiked in vermilion tones as well as her skin lightened in a pale tone, as for her face, it is slightly denoted by curved black marks on both cheeks and forehead. Kibutsuji couldn't hold back the urge to stroke his children's hair while listening to the beat of their breaths, and that's where he swears to protect himself and wants them to become excellent subordinates, because to him, they aren't only his children. They're part of his army that only occupy a privileged position.
"I think it's time to start your training," the man whispers decisively.
There was an extraordinary meeting of the twelve moons, he did not care if most of them did not show up and that applies to the lower moons. When their presence appeared, most of them had the same thought: Who are those 2 sleeping children of which are on the legs of their boss?, None were able to ask that question for fear of retaliation.
"I know you are wondering about these youngsters. I'll say it just once so don't even think about asking for replays. From now on, you will watch and teach everything to them: physical and mental training, handling of the blood demon arts and everything related to our species and our enemy. Take care of them, and I will have no mercy if something bad happens to them."
Wait ... train them? Take care of them? Are they babysitters or what the fuck? At what point did the powerful warriors and feared moons turn into having to be teachers and caretakers of a pair of brats who were unaware of their existence until now? For a moment they thought it was a joke or something similar ... but his boss's tone of voice indicated otherwise.
"Excuse the intrusion but ... Who are you and how special are you?" Ask respectfully the upper moon 2, Douma.
"Let them answer your question" To everyone's surprise, the fearsome Muzan whispers softly to his children to wake him up and it was too shocking that the most terrifying showed a side ... Out of the ordinary?
"5 minutes more" the girl murmurs sleepily while the boy opens his eyes lazily. Young people wake up slowly, ignoring what is happening around them.
"What is it?" Asks the young man with long black / reddish hair.
"I want you to introduce yourselves to what will be from now on, your new family" The brothers observe the infinite fortress as well as its inhabitants, for some strange reason, they had to dry the saliva produced by their mouths and ignore the appetite that began to expand in their stomachs.
"It is a pleasure to meet you, my name is ... let me introduce myself first. Stop imitating me! Then do it yourself!" Kibutsuji's subjects try to keep their stance in the face of that strange situation as their boss clears his throat to stop the discussion.
"Ahem ... manners above all. The oldest first" The named smiles arrogantly at his sister, who responds by sticking out her tongue.
"As I was saying, my name is Tanjiro and she is my sister Nezuko. It is a pleasure to meet you and we hope that you will take care of us" With respect, he bows to those who would be his new family, something that his sister imitates.
"Just as you heard. Tanjiro and Nezuko will live in this place and you will educate them as they should."
"A question, will they be ... our replacements?" It asks without any shame the Lower Moon 6.
"It could be ... but no. They have the highest position of all, although it is normal that they did not say their full names" Kibutsuji's rictus glance at Tanjiro caused his sister to hold back the laughter.
"Complete names?"
"Yes. Tanjiro and Nezuko Kibutsuji. Therefore, they are my children" That revelation was somewhat shocking. Children? It was a joke?.
"Since ... you have been doing ..."
"I got them? Two months ago, I saved them from a tragic fate. They lost their family and being close to the place, I was able to save them by giving my blood. Any problem with that?" The refusal of the inferiors and some of the superiors was the starting point for the beginning of the new life of both young people in the fortress.
As time went by, the brothers not only became stronger at all points but also wove bonds of affection with the moons (more than all the upper moons), they saw them as their family and greatly appreciated their teachings and moments.
* Kokushibo: He teaches Tanjiro how to use breathing as well as sword handling. With Nezuko, he works the way to dodge and counterattack in the case of facing a demon slayer. To the surprise of the former slayer, Tanjiro can use the sun breath due to the memory inheritance of his ancestors, so it took a long time for the black-haired and burgundy young man to correctly use that new power without harming himself and with others. The brothers respect the Upper Moon One and fascinate them in hear stories from his past.
* Douma: Despite the fact that they both found it strange the lack of emotions on that moon, they learned how to resist before poisons and pain, the anatomy and functioning of humans and demons, as well as resistance to some adverse weather conditions (More than anything the cold for his blood demon arts). Douma loved to tease them and occasionally took them to his temple although, he is disappointed and at the same time fascinated that they both did not eat humans.
* Akaza: He trains both of them in resistance and physical combat even under pressure. For the pink haired boy in the beginning, he thought that those 2 were weak and it was not worth spending his time helping them, but since they were children of his boss, he had no other choice but to obey him. With the passage of time he was surprised by the progress of both to such a point that they were just short of reaching their level, which made him proud. The brothers love the upper moon Three fondly and have fun arguing between the Upper Moons Two and Three, especially when Akaza shatters mercilessly Douma.
* Daki and Gyotaro: As they have the connections for having a family (Brothers), they got along quickly. Tanjiro and Nezuko become frustrated when the Upper Moons Six argue over anything and have to mediate for them to reconcile. Daki and Gyotaro teach stealth as well as camouflage to hide their demon form and appear human.
* Nakime: Although the guardian of the fortress has nothing to teach, the young brothers love her and consider her as an older sister. They love to hear the melodies coming from her biwa as well as the use of her blood demon arts to manage the fortress. The demon with long black hair is ashamed of those deals of the boys, however, inside she welcomed the warmth provided by her boss's children.
* Rui: He was the only one of the lower moons who dealt with the brothers. He knew very well that he couldn't give them the option to join his spider family but, Tanjiro and Nezuko (Especially the first one) accept the Lower Moon Five as a younger brother. The time they spend with the two enjoyed it and I even opted for Tanjiro's advice not to be cruel to his own family when they met them, there are also occasions that they train him in combat.
The rest of the Lower Moons and Upper Moons Four and Five were not to the liking of their boss's adopted children. They kept his distance from and to them and they did not care what they do.
TO BE CONTINUED IN THE NEXT PART.
Sorry this but I opted with the option to divide this chapter since it is long (I wrote 6K exactly), soon I will upload part 2 of the chapter.
By the way, I couldn't do it in the previous chapter so I better do it now!
Taisho Secrets!
* Since they were transformed into demons, they went 2 months without leaving the room that Kibutsuji made for both of them, since he hoped that they could assimilate both their new identity and insatiable hunger. Occasionally, Muzan led them outside the fort to adapt their senses. (If it can be said that way).
* In the following month, it was the first time that Tanjiro and Nezuko left that room to see the infinite fortress as well as the twelve moons. Here is the first hint of what our brothers would eat, and that over time, they hypnotize themselves so as not to eat their new family (Although there were moons that they did not like, they were part of the family, unfortunately for both of them )
* Muzan at first, he hated the idea of considering Tanjiro and Nezuko as his children since for him, ALL DEMONS are his subordinates that he could cast off at any time if he didn't show the power he wanted. There was a point that he preferred that they be part of the Lower Moons, but he realized that putting them with lower people would not show the true potential that was hidden in both, he also thought to put them as Upper Moon Zero. At that point, he explored in his mind multiple possibilities so in the end (And after seeing a stage play with his human "wife" about the family), he chose to adopt them. In the future, he will accept that his decision was the best he could have.
That's all for now! see you with the second part! Bye!