S3 You Don't know Us (Kny x Fem!Demon!reader x Bnha)

A/n: I'm alive ᕕ( ᐛ )ᕗ

The next couple days were smooth at the Agency, Rui Training with everyone taking turns. And occasionally going out for a small mission or something.

But the thing was, the heroes has been reported to by the people that the creatures of the night were starting to appear more and more.

More and more hero Agency's came and asked for the Kibutsuji's help, but they care? No. Why would they.

And now for another news flash, The Hero Killer was starting to become very popular. But he was very hard to capture.

"Nee-Saaaannn" Rui Whined.

"Haaaiii?" (Y/N) dragged out.

"Can I go fight the Hero Killer? Please? I wanna kill something! Or as close as you can get anyway.." Rui said.

"Oh? Is my Ototo hungry for blood lust? It's fine with me but go ask Otou-San." (Y/N) replied.

"Ok." Rui said happily before going to ask Muzan.

"Sigh, how long till this ends? I wanna go somewhere else, this has dragged on for to long." (Y/N) said to herself, before she heard footsteps running towards her.

"Otou-San said yes! And he's very proud of me!" Rui exclaimed.

"Nice. Bring Mui with you though alright."

"Hai!"

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"Woah, it's just chaos out here. I like it." Muichiro said.

"Mui-Nii, let's just find the hero killer." Rui said.

"Ok."

After a while with sniffing blood, they found themselves in an alleyway. With a fight that was going on.

Five people were in the alleyway, The Hero Killer, The pro hero: Native, Midoriya, Todoroki, And Iida.

Rui and Muichiro wastes no time and jumped right into action.

"Breathe of Spider: First form: Eight-legged slash!"

"Blood Demon Art: Mist Body."

Rui managed to get eight very deep cuts on different parts of the Hero Killer, while Muichiro turned himself into Mist. Then reappeared on the Hero killer's back.

"Breathe of Moon: First Form: Evening Palace."

Muichiro unsheathes his own blade and slashes in front of the Hero Killer And let Sharp moons cut him, Rui then sheathed his blade back up again and prepared to use his Blood Demon Art next.

"T-The M-Mist Hero: T-Tokito?!!?!" Izuku stuttered.

"Get your ass off the ground, and the fuck out of here. Me and Rui will handle this." Muichiro said harshly.

"But Tokito-San-"

"Shut the fuck up and go!" Rui and Muichiro both yelled in sync.

The three students flinched at the tone, they carried Native and ran away to get help.

"Well, if it isn't The Famous Mist Hero Of the Demon Slayers group. And you got a student with you now huh? Pretty impressive, but your just like the others! Your not any different!" The Hero Killer yelled.

"One, Shut The fuck up, your voice is annoying me. Two, this is my brother your talking to. And three, I have encountered and have been dead before so I don't really care." Muichiro said with a straight face.