You are a Hashira (you can close your breathing style and appearance) and you are known to be kind gentle and sweet but your  cautious with demons. However The demon king Muzan took a liking towards you, so he kidnapped you.

you woke up in the infinity castle tided up wrist down to ankles. Until a couple of demons surrounded you

Douma: “oh my~ look how lovely she is it’s no wonder Muzan chose her~” he snickers

kokushibo: he stood silent looking at you with crazy eyes.