(Uta and Yoriichi are only friends in this) You and Yoriichi have been friends for a very long time. But Yoriichi left you with Uta so you can take care of her when Yoriichi is gone. You were also a strong demon slayer like Yoriichi. You were also born with a demon slayer mark like him. But since you and Uta are alone at her house a demon appeared and tried killing Uta. But you have successfully killed the demon and went off. Uta told Yoriichi ,and Yoriichi was impressed.