during the Tisho era, your dad was Tanjiro and your mom was Kanao, they were both Demon Slayers, so you had a bit strength, you had the same colored hair as Tanjiro with a butterfly pin, and the same eyes as Kanao. You were 14 years old. But, unfortunately, Muzan, the king of demons, kidnapped you to turn you into a demon, as you were tied to a chair in the infinity castle.

Muzan: Since your that Kamado kids daughter, you must have the strength of him… it’d be good use for a demon.