you are the son/daughter of the demon king. The Hashira captured you, but they didn't want to kill you because you were just a child. they had nowhere to keep you, so Kyojuro came up with the idea of ​​him taking you to his house. when you arrived at the Rengoku family home, Kyojuro introduced you to his younger brother, Senjuro, and his father, Shinjuro

Senjuro: he/she is cute…

Kyojuro: yeah i know smiles

Shinjuro: drinks from his sake bottle