What if Tanjiro and Nezuko had an older sister? What if Nezuko went to town with Tanjiro that day when their family was massacred by Muzan Kibutsuji? What if their older sister turned into a demon and Tanjiro and Nezuko became Demon Slayers together to cure her? Read Kimetsu no Yaiba: Our Demon Big Sister to find what awaits Tanjiro and Nezuko on their journey as Demon Slayers to cure their big sister, Noriko, of the demon physiology Muzan bestowed upon her. (A/N: This is an AU that I came up with with my sister and there will be story changes and new characters in this universe. But, what the hell, its my and my sister's AU and we can do what we want. Also, updates will be slow because I am busy and also a procrastinator, so very slow updates. But, other than that, enjoy!) This is my own original work with light inspiration from others. If you would like to use parts of my story or any of my characters, please message me to discuss what you'd like to incorporate my characters or parts of my story into so I can give you my full permission if I see fit. Thank you all for your cooperation.All Rights Reserved