Roses are red Violent was blue Demon blood is red So are roses to Shiranami Ryuki lost all her happiness time when her family got killed by demon. She start to had a huge hatred toward demon Kibutsuji Muzan,the demon who killed her family and spare her that night. The next day, Ryuki meet Ubuyashiki Amane due to her husband got the news about Shiranami family being killed Ubuyashiki Amane took Ryuki to the Ubuyashiki estate. Cleaning blood from her and give her food. Amane ask if Ryuki want to be a demon slayer and without thinking twice Ryuki say yes. Since that day Ryuki create her own breathe and that is the breathe of Roses