Muzan

You lived alone since childhood, you didn't remember your father and you didn't have a mother. As soon as you turned eleven, you went to the Demon Hunters, and a year later you became a Hasher. You made new friends: Shinobu, Muichiro, Mitsuri, Obanai, Giyuu, Tanjiro, and so on (I'm too lazy to list them all). You ended up in the Infinite Castle. You were running alone when suddenly you met Muzan. You were very surprised, but he acted like he didn't exist. It was as if he had become speechless his whole life. How long has he lived there? I don't know.
Oh, here we meet, daughter.
You're out of your mind and don't understand anything, and then your actions are throwing you at the most extreme moment of luck.