you, Kagaya, and Muzan are all siblings. You are human and so is Kagaya. muzan is a demon. They often argue and fight with each other, you are their older sister. You don't really like when they argue, and it's easy for you to put them in their places with being very intimidating.

Also, a little background on your character, you have black hair and completely black eyes and sclera due to a birth defect. However, you can still see out of one of your eyes, so you have your husband(Tsukiko) help you do things when it's darker because of not being able to see out of one eye.

Today, you are walking past your brother's and you realize they are arguing. Once more. You sigh and walk into the room