New Adventure with A Demon in Superhero World! || BBB x KNY x BNHA Crossover AU

Prologue

It's been almost 2 years since they defeated Muzan Kibutsuji, the Progenitor of Demons, the Demon Slayer Corps was officially disbanded three months after that.

16 years old Nezuko was sitting on the picnic mat, waiting for the boys to come back.

She was happy that they found peace within them again. Even though Yushiro, a very last demon who was still around, she hoped that there would be no more demons. She hoped nothing would be gone wrong as it was already been almost 2 years.

She was smiling while admiring the morning views and that was where it started went downhill.

"Well, hello there, 'The Chosen Demon' who was actually never devoured for once and could conquered the sun," someone in deep voice could be heard behind.

She instantly went alerted and whipped her head around to see the person. The said person was nowhere to be found. She stayed silent for letting the said person continued.

"Hmm... It was such a waste that you really despited demon which made you refused to devour human," he continued. She still refused to answer him.

"Besides, Muzan Kibutsuji was supposed to be my favourite... Oh well, it's useless now. How about you become my new favourite-"

"No way! Go away and it's possible for me to turn into demon again!" she talked back to him. She knew that she immuned to Muzan's blood but she would definitely turn into demon again!

"Pfft, this is why I should send you to another world instead, where all of the human in that world have no power to defeat any demon like you. YOU, should be their new Demon Queen, just like this favourite demon of mine, Muzan Kibutsuji," he responded coldly to her.

"Never! Even I turn into demon, it is impossible! Even it is possible, I will never devour human and turn them into demon too!" she fiercely replied back without fear.

"Fun fact, I already got all the remained Muzan's blood from your beloved older brother, Tanjirou Kamado earlier," a hand suddenly appeared in front of her, despised that it was his hand who only showed up instead of all of his appearance.

There was a small pool of blood, floating on his hand. She was taken back as she still recognised this blood, it was indeed Muzan's blood. Just who was this person?

"As I expected, you would ask who am I in your mind. I feel... no need to introduce myself to you. I don't even mention your name yet," he still continued. She wanted to facepalm so bad, this was very unnecessary!

"I'm not joking. I will 'inject' this little precious blood to you right now, see whether you still worth to be given a name title as 'The Chosen Demon'," the blood was suddenly shot to her forehead.

She was very unwared of that as it was happened in the blink of eyes. She couldn't feel anything at the moment, her mind went blank as there was someone controlling her.

Her nails suddenly grew and sharpened, her fangs also grew and showed a very pointy fangs. Her salive was running down to her chin as she was out of control.

"Wonderful! See, you still can stand under the sun even you are completely back to demon! Time to clone you just for this little world as I, *****, will send you to another world to become their new Demon Queen! Say goodbye to your little world," in an instant, another Nezuko suddenly appeared in front of her.

She still hadn't processed what happened just now as she feel her neck being slashed using a hand as it was like a knife easily cut a meat.

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