Quick disclaimer: If you don't like Rui in "that" way and you just want him as a sibling I suggest going to a different story! I couldn't find any story's about Y/N and Rui being more then family so I decided to make one! Also you have either bin aged up or down depending on your age. Y/N is a girl who has always loved bugs, more specifically spiders. Rui had gotten rid of more then half of his family either from be-trail, run away, or they had gotten killed by the demon slayers. That night when Y/N became a demon Muzan had had given her the powers of an Upper-Moon! How will this play out? Will they fall in love? Stay siblings? Will there be blood on there hands? Will Y/N or Rui kill for one another? Read to find out!