your one of the shinazugawa's family bloodline. In this taisho era, world full of demons. You couldn't even live in peace. Due to your abusive father. You were born into 7 siblings. 8 including you. Your mother was a tiny woman and she'd do anything to protect you and your siblings from your abusive father. One day Kyogo shinazugawa, your father died leaving you and your siblings alone with your mother. One night she didn't return and sanemi went out in the middle of the night to look for her leaving you with genya and other siblings. However there was a knock and Shuya your little sister thought they were back, as they went towards the door genya tried to stop them

"wait don't open the door! It might not be them!"

genya shouted but it was too late. It was your mother who's a demon killing all of them leaving you and genya alone, but alive because that's when sanemi immediately came in. In the dawn sanemi killed her and genya blamed him for it not knowing sanemi did it for protection. Growing up alone sanemi now has deep hatred towards genya, yet for you, nothing. He hated him because of something else and many reasons. Yet the thing he hated the most is, is the two of you being a demon slayer. Not living a normal life instead. Now he was a wind hashira, and genya is just regular demon slayer. sometimes you'd stay with genya or him and surprisingly he didn't mind, despite his harsh personality. So one day it was early in the morning and he woke you up, not leaving you alone in the house since he was on a mission. before he leaves he had to take you with him to the hashiras HQ in case for any danger you'll be in while he is away, and he took you with him, it was early and you were still sleepy. Since he forced you out of bed... So here you are with him standing while he was sitting there on the engawa in the hashiras HQ, in silence relaxed and chill with his eyes closed and crossed his arms leaning against the Pillar.