Demon Slayer: Daki's New Sisters (Patreon)

“Arghh! I'm too weak!” Tanjiro yelled in frustration. After what happened on the train Tanjiro left for a period of self-training. He blamed himself for his weakness which caused his allies to die. Knowing that he would only be a burden he left in order to become stronger. Though even with all this time alone he felt as if nothing has changed. He needed to grow stronger you just needed to. There had to be a way. There just had to be.

“Kaww! Kaww! Demon spotted in Yoshiwara! Demon spotted in Yoshiwara!” Tanjiro’s crow cried. Landing on his shoulder informing him of where his next destination was. Seeing that this was a good way to test his skills Tanjiro decided to head out not knowing what was waiting for him there.

The moment that Tanjiro reached Yoshiwara he smelled the faint scent of Oni in the air. As he traveled throughout the city the smell grew stronger and stronger. Knowing that they were there and possibly a threat to the people around the city Tanjiro wasted no time in rushing toward them.

After several minutes of running Tanjiro finally found the strongest scent of the of the Oni. However, he was surprised to see that the area around him felt dark and sinister inside that of an entertainment district.

“Fufufu~. It would seem that you finally arrived,” Daki said looking at Tanjiro.

“You! Who are you?” Tanjiro yelled at the only who was dressed in a very risqué attire.

“Me? I'd be more concerned about who I serve rather than me~,” Daki said. He was quite the cutie but she would have to wait to make him hers. “My master has ordered me to take you in and make you one of us. He sees potential in you and can’t wait to see what will happen when you become me~.”

“Shut up you vile demon!” It’s time to die,” Tanjiro yelled as he began to fight against Daki. To their surprise, she was much stronger than she appeared he used every amount of strength that he could but no matter what he did he could not gain the upper hand on her.

“Hmm, much weaker than I thought you would be, though perhaps as my twin we could rival as equals,” Daki said, teasing him as she jumped up to the rooftops causing him to chase after her.

“You’re not getting away!” Tanjiro yelled at Daki as she ran away.

“Stand your ground and fight me!” Tanjiro yelled, still chasing after Daki. “Just like a demon to run away when it knows it can’t win!” Tanjiro yelled, getting trying to goat her to fight him.

Though Daki didn't care, she refused to let the young boy's insult bother her as she kept running. She looked back at Tanjiro and smiled. He was falling for her act easier than she had ever expected. However, it was time for her to end this charade. While she couldn't fight him head-on and forcefully transformed him she thought this method would be much more enjoyable.”

“Over here~,” Daki said, stopping on a suspicious rooftop, compelling him to charge at her.

“Finally! Now we finish this!” Tanjiro yelled charging at her, but the moment that she got close, she jumped out of the way revealing a giant mental cage with a heart-shaped bed below them. Unable to stop himself, Tanjiro fell right into the cage. As he fell Daki quickly disarmed Tanjiro of his sword before completing his capture.

“No how is this possible!” Tanjiro yelled out in despair. He was embarrassed that he was easily overpowered by a female demon. He hated that he was so weak so much so you wish that this was nothing more than a dream.

“It's very possible,” Daki said to him closing the cage so he couldn't escape. “While the flight was quite fun I do believe that must finish what my master ordered me to do. It's time that you become one with me it's time for you to become my new sister~,” she said overpowering him and pushing him onto the bed.

“Stop this! I don't know what you have planned for me, but I won't be a part of it. Or rather die than become your sister! Go to hell you ugly hag!” Tanjiro yelled at her.

“You fucking little brat! How dare you call me an ugly hag!” Daki yelled at him, her anger rising. She was the most beautiful woman and demon in the world! To call such a refined beauty as herself an ugly hag was inexcusable!

“Go on you ugly hag, kill me!” Tanjiro yelled at her, ready to die for his failure. There's a demon Slayer who cannot kill a demon death is the only thing to expect. At least he could die knowing that his friends would take care of his sister for him once he was gone. Perhaps that would prove to be better than he ever was.

“Twice now, you have called me an ugly hag, and now for the second time, I shall forgive you,” Daki said to Tanjiro’s confusion. “I have no plans on killing you, my master has plans for you, and so do I. Wasting potential like yours, there's something I will never make the mistake of. Though you shall be punished for insulting my beauty~.

“What the hell are you talking about? Kill me, you ugly hag! Do it!” Tanjiro would not let her have her way. He would die with honor!

“…Fine if you don’t wish to take this as a gift then this shall be your punishment,” she said, coldly looking down at Tanjiro with a cold harsh expression on her face. She willed her obi sashes to attack him. 

“Please stop! Just kill me!” Tanjiro yelled as the obi sashes began to wrap around his entire body, binding him in place so he could not escape! Daki smiled; it was time to begin. He would soon see things differently and repent for calling her an ugly hag three times.

“Mmmmmmph!” Tanjiro tried to scream for help as he tried to struggle free from the obi sashes, but it was no use. Before he could do anything, Daki injected him with Muzan’s blood as well as her own, the cute she made on his face. And thus, she began the demon blood art transformation~.

Tanjiro was scared and confused. What was she planning to do with him, and why the hell? What's his body feeling like it was on fire? Both scared and most was that he did start to like it he didn't know why? It was as if something was awaking in him, changing and corrupting his soul! How was she doing this!?

“Oh my, look at that face you're making~. I can tell someone's already having fun,” Daki said, slowly stripping him of his clothes. “Tsk, your voice from my master's orders I probably would have kept you for myself~.”

“Nnnnh~!!! No! Stay away from me!” Tanjiro yelled, trying to fight off the foreign blood that was flowing through his veins, but with each passing second, you could feel his body become weaker and weaker.

“Still ever the resistant one~. Worry not, soon you'll be begging for it to continue~.” Daki couldn’t help herself. Tanjiro was perfect. His expression of resistance against her mere beauty allured her.

Tanjiro’s body began to shrink beneath the obi sashes. He screamed more and more as his body began to feel like it was on fire! His frame became more feminine as his hair and nails started to grow longer.

“Mmmmmmmmmph!” Tanjiro screamed and moaned in horror as a pair of D-cup breasts the same size as Daki’s grew on his chest. Tears rolled out of his eyes, and she was unable to resist the urge to grope them. If Nezuko saw him now, she would most likely be appalled.

Seeing the tears form in his eyes Daki wanted to humiliate him more. She shoved her tongue down his throat while biting his lip, fattening it up to be as beautiful as hers as purple lipstick was permanently etched over them.”

“Mmm~. Not bad~, You taste quite delicious~,” Daki said teasing him, watching his face turn bright red!

“Nnnnh~!!! L-let me go!!” Tanjiro yelled as Daki was scared, noticing that his voice sounded just like hers now!

“What the hell are you doing to me!? Let me go! Let me go!” Tanjiro cried like a whiny little girl, much to Daki’s amusement. Tanjiro knew that his body was becoming that of a woman, but he hoped that if he could escape, he could stop this, but he was wrong. Daki would never let this stop even if he could escape.

“There’s no point,” Daki said, teasing him and ignoring his demands, as he was nothing more than her doll at the moment, whose only purpose was to be shaped by her. Muzan gave her the perfect subject, and she would do with him as she wished.

“Stop! I’ll-mmmmmph!” Tanjiro screamed one last time as his ass and thighs expanded out to the same size as Daki’s, and then with one painful moment, Tanjiro’s manhood was no more! Tanjiro felt a part of his mind shatter as Daki smiled back at her new twin. Thanks to her master she now possessed the loveliest of twins.

“Time to come out and see the new perfect you,” Daki said, releasing Tanjiro and holding up a hand mirror for her sister to see her new form~.

“No… no way,” Tanjiro said, shocked to see that she now had the exact same face as the demon that she called ugly. In her horror, she unconsciously began to look down at her breasts before she began to fondle them as well as her new fat ass to make sure that they were real. With each squeeze, waves of pleasure went throughout her new body!

Daki watched her new sister fondle herself with delight, and she had to hold herself back from pleasuring herself as well. Now was not the right time as such activities would be done during her “training sessions". While her sister may now possess her body, there was still a lot of work for her to do to make her accept her new form.

Out of the corner of her, Tanjiro saw Daki smiling at her, taking her out of the pleasure trance that she put herself in. This wasn’t right! This wasn’t her! She had to focus and fight back so that she could return to normal! Tanjiro rose to her feet as she looked at her. Daki was right there, and breasts or not, she would-

“Kyaaaaaa!!!!!” Tanjiro screamed at the top of her lungs in Daki’s voice, realizing that her old hey had slipped right off. She tried to cover herself with the remains of her clothes, but it wasn’t enough. Tanjiro fell down to the ground and held her knees to her chest, hoping that no one would see her like this.

If her friends saw her like this, she would never hear the end of it. No wait, it would be worse if Nezuko saw her like this. Nezuko would lose all respect for her as her big sister! Wait… big sister? Tanjiro was her big brother, not her sister. She was starting to become more confused due to her current situation.

“Aww, how cute,” Daki said, mocking Tanjiro. “I remember when I was that shy and innocent. However, there's no reason to be afraid. This is something that you should want~. You should be thankful that I gave you such an attractive new form and a powerful one at that. I even modeled you after my image, isn’t onee-chan kind?” she asked, further toying with Tanjiro in her fragile state. She couldn't resist whenever she saw her twin's scared face look at her it was as if she was begging to be tormented.

“Come on, you know that you like it, no you love it don’t you?” Daki asked Tanjiro, teasing her. “I saw you squeezing your new tits and fat ass even though you knew that I was here. You couldn’t resist, could you? I mean, really, who could? It's only natural~.”

“N-no I-I di-didn’t mean to!” Tanjiro yelled. She began stuttering as she could no longer deny what she did or what she was. She fondled herself and got lost in the pleasure of her new form. A form that was not human. If Daki modeled Tanjiro's new body after herself, that meant that she was now a demon!

“Pfft! Hahahahaha~!!! It looks like someone just realized that they’re a demon now. Oh, I’ve seen that expression many times before. Can you feel it, can’t you? That sense of being reborn and your body overflowing with power!”

“No I-I-I’m a human!” Tanjiro yelled at her trying to avoid the truth. She desperately wished that this was nothing more than a nightmare.

“Are you really a human? Then tell me, human, what do you think about this?” she asked, flicking a small amount of human blood onto Tanjiro’s lips.

“Ahhhhhhhhhhhh!” Tanjiro moaned in pleasure unable to resist the wave of pure ecstasy that washed over her body. She never felt this way before and even thought it was possible to feel this way. She had tasted only a small amount of human blood, and she had felt more alive than when she was a human. It heard her pride as a demon Slayer to meet but this feeling that she was experiencing right now as a demon made her feel more alive than she ever did before.

“N-no! I can’t Tanjiro yelled out, trying to resist some more, but before she could do anything Daki forced her obi sashes inside of him through the cut in her face. As it did Tanjiro’s hair became white and his resistance weakened.

Tanjiro tried to fight it, but it was pointless. Nothing she could do would stop her transformation now.

“That’s a good girl,” Daki said, caressing her twin’s face. “There is no reason to resist when you know deep down that this was what you had always wanted. You hate how ugly you were as a human and that you've vented your frustrations out to anyone that was more beautiful than you. The ugliness as a human engulfed your soul what is a demon that ugliness is gone and only beauty remains. Resisting is pointless. All you have to do is listen to onee-chan, and everything will turn out fine.”

With that last bit of encouragement and mental manipulation, Tanjiro’s mind became corrupted just like her body. The blood demon art had transformed her completely. Her body felt another wave of ecstasy wash over it as she began her awakening. A third eye in the middle of her forehead opened up and for the first time in her life, she could finally see.  Her mind no longer resisted her new form or nature. She'd finally reached who she was always meant to be. The shackles that bound her down as a human no longer exists as a demon. She could do whatever she wanted.

“Hahahahahahahahahahaha!” Daki laughed maniacally, watching the former demon slayer embracing her new life as her new sister. Together nothing would be able to stop them. And they would serve their master forever~.

“Now you need to learn what it means to be an actual lady. So you're going to follow your onee-chan’s example and become a beautiful Oiran willing to do whatever she is asked of~,” she said to her crying sister.

“Yes!” Tanjiro yelled, unable to resist.

“Good girl~. Now Let’s get to work~.”

-1 Week Later-

One week had passed since Tanjiro was turned into Daki’s twin younger sister, and she had finally realized how powerless she truly was. While she was now physically stronger than ever before, she was still powerless to disobey her onee-chan. Tanjiro one nothing more than to go back to her friends and her own sister, but her onee-chan wouldn't allow it. Onee-chan Tanjiro to fill in as an Oiran named Taki.

Daki told her that it was for practicing discipline and so that she could learn the true ugliness of humanity. At first, Taki felt humiliated having to wear her onee-chan;s used clothes and having her feminine hair tied up tight like a mature Oiran, but soon she started to like it.

While working as an Oiran, she actually began to enjoy herself as a refined lady. However, this enjoyment came at a price. The longer she stayed in this form, the more and more she began to see what her sister was telling her. Humans were scum. They treated those beneath them like dirt without even acknowledging what they'd done. Daki’s master always saw even the tiniest bit of usefulness in every demon that worked under him. Humans didn't bother. They liked to flaunt the power that they thought they had, tormenting those that didn't. Demons didn't care who or what you were. They just killed in ate such what's their nature.

Taki didn’t want to admit it, but she loved eating the pretty girls that her sister gave her, though she never understood why. Why did she care about onee-chan, after onee-chan had made her act more and more like her each day? Why did she feel safe when onee-chan would come into her room at night after she had cried herself asleep to lay down with her?

As for today, three more people were slaughtered by Taki using her new control over her obi sash. Their blood splattered across the room and across both sisters.

“Ahhhhhh!!!!” Taki moaned in pleasure as the blood rained down on her. She opened her mouth and drank as much of the blood as she could. Unable to resist the urge any longer, she transformed into her demon form and started crawling toward her sister, enticed not only by the blood she was covered in but by her body as well. Daki being the good onee-chan that she was, couldn’t refuse her.

Daki shoved her tongue straight done Taki’s throat before pushing her down onto the bed. She began her lesson by showing her dear little sister the proper method of using her tongue.

“Nnnnnnnnnnhhhhh! Ahhhhhhhhh!!!” Taki moaned with pleasure as her sister went down on her, making her experience a form of pleasure that she never had before. She wanted to resist this urge, but it was just too powerful. With each turn of her tongue, she began to crave more. Shen wanted this! She wanted onee-chan to dominate her like the slut she was!

“M-more! More! Give me more!” Taki yelled as her onee-chan showed her the biggest perks of being a woman.

Several days passed after that, with Taki had fully accepted her role as an Oiran.

“There you are,” Daki said to her little sister as she entered her room. Daki was in her awakened demon form laying on Taki’s bed. Taki, who had been thoroughly conditioned over the past several days, started to strip down, but Daki held her hand up for her.

“No, not yet,” Daki said, knowing that she was teasing her sister. “I came here to tell you that your former younger sister of yours has arrived. Would you like to see her~.”

“May I~,” Taki said, wanting to showcase her new form to her former sister. Nezuko would be speechless. Well, that is saying if she could talk in the first place~.

“Fufufufu~. I know what you're thinking in that dirty mind of yours. Your thoughts are the same as mine so you must know what I have planned,” Daki said, seeing if this would cause Taki to react in any way.

“Yes, onee-chan,” Tanjiro said obediently as she began to naturally smile like the professional Oiran she was made to be with clients. She had learned better than to disobey her onee-chan and that her onee-chan knew what was best for her. If she had to be nothing more than an Oiran, she was more than happy to do so in order to make her sister happy. If transforming her former sister into a twin of Daki just like her, then so be it~.

“That’s a good girl,” Daki said, caressing Tanjiro’s cheek. “For being such a good girl, I believe that you have earned yourself a reward,” she said, squeezing Tanjiro’s fat ass before ramming her tongue down her sister's throat. “Come along. It's time for us to meet our soon-to-be sister~.”

“Mmmmmmppphhhh!!!! Mmmmmmppppphhh!!!” Nezuko struggled against the obi sash that held her in place in the next room over. When she saw the door open, she expected to see her older brother rush in to save her as he always did. But instead, she was shocked to see her captor Daki come in with a girl that looked just like her.

“Mmmmmmpppphhhh!!!!” Nezuko, while a demon, still cared very much for her older brother. So much so that she was willing to escape the other demon slayers in order to find him, it was a hard journey and one which she thought would never end, but she was happy when she heard the news of the demon that captured demon Slayer with a mark on his forehead. She had hoped by confronting this demon, she could find the whereabouts of her brother, but instead, she was easily captured without a semblance of a fight.

“Aww, is someone still struggling I see~,” Daki said, mocking Nezuko as she and Taki walked up to her. So my dear sister, what do you think of your gift~. Daki need to know if Taki was completely on her side. If she tried to free her former sister, then go back to re-educating her, but if she decided not to, they could have the fun of training their new sister together~.

“She’s lucky to be our sister,” Taki said overjoyed.

“Fufufufu~. Dear little Nezuko, can you tell who this is in front of you~,” Daki said, teasing Nezuko. “That's right, this right here is your former older brother, my new younger sister. I transformed her into a demon using a special blood art transformation from our master. It didn't take long to make her obey me. To make her worship me. To make her want to be me. She's now a loyal servant to both Muzan and me ~. Isn't it wonderful~?”

“Grrrrr!!!” Nezuko was furious. How dare this demon transform her older brother into one of them? She would die for this!

“Now, now, that’s no way to treat your older sisters~,” Taki said, teasing there soon to be a new sister. “Now open wide~.” Taki ripped off the gag covering Nezuko’s mouth and forced her to ingest the blood of Muzan and Daki.

“Now let's begin~,” Daki eagerly said Nexuko’s body became warmer.

Nezuko was unable to resist as both Taki and Daki stripped of her clothing before pushing her down to the ground.

“Grrrrrr!!!!!” Nezuko tried to fight back often, nut her arms felt like lead, and she was unable to move. It was impossible to fight back. There was nothing she could do except for her accept her fate. No, that wasn't like her. Nezuko fought back as hard as she could, but the twin sisters knew how to make her obedient. Within mere minutes after injecting her with the blood, Nezuko had already begun her transformation. Bit by bit, her body changed, growing bigger as D-cup breasts filled out onto her chest. Her body became more sexual and curvy in nature. And so did her sexual drive. Her hair grew longer, and her body became mature.

“Grrr! Stop it, you bitches!!!” Nezuko yelled in frustration. It took her a few seconds to realize that these words were no longer in her head but being screamed at the top of her lungs.

“My, my, my, would you look at that~,” Daki said, happy to see that her youngest sister finally grew a voice box. This made communicating with her that much easier. As well as this would most benefit her master. She knew that neither she nor her sister Taki was told to capture Nezuko and transform her into the third sister, but she did not care. She knew that her Master would praise her regardless, having both siblings under his control far more beneficial in the long run than would be not.

“Shh, now, dear sister. You can't deny that you feel good now, right~,” Taki said to her. Trying to convince her to join her side. Just look. Thanks to her you regained your voice~. Doesn't it feel good to talk again? Doesn't it feel good to have a body that's strong? Doesn't it feel good to have a body that's beautiful~? A body that will never be taken advantage of by humans ever again. Humans that want you dead just because you're a demon. You never chose me, yet they prosecuted you for it. They hate us for what we are. Don't you want revenge~?

“I-I-I do,” Nezuko Said falling underneath the blood art spell. It didn't take much effort after that to make their new sister Naki believe that they were always sisters. Under their master's control, they would lure Demon Slayers into this establishment and get them one by one right underneath the demon slayers' noses. They would dominate Yoshiwara as the three beautiful Oiran sisters~!!!