Y/N L/N, originally Y/N Tsugikuni, was the daughter of Yoriichi, but she was turned into a demon. Having broken free from Kibutsuji's curse, she joined the Demon Slayer Corps. What else will she face?

She lost everything at one night but received something at that night. A demon killed her family but she was saved by a man who promised that he will protect her. He taught you Total Concentration Breathing and Breathing Styles. One thing that you know is that,the man who save you is a demon that is stronger than Muzan,himself. With a lot of power you and him become the same title Hashira or more like a duo that never separate. What will happen when the war between demons and humans are getting closer and closer?What will happened when some of the volleyball players become a demon slayer? Read it to find out! _______________________ I don't own Haikyuu or Demon Slayer. Please don't copy my stories ideas. I don't own the photos or video of this story so credit to the owners.