Kawa lost her parents when her home was attacked by a demon when she was only 12 years old and turned into a demon herself, so her brother Kenji, who is 4 years younger than her, became a demon slayer and wants to turn her sister human again.

It's been 3 years, Kenji is now a wind breath user, Kawa is a demon who can control herself, but Kawa does not eat people or consume blood to replenish her energy. normally eats human food, which demons abhor.

Anyway, things happened while Kawa was sleeping in her box as usual, you already know this part, now, for tonight, Zenitsu, Tanjiro, Inosuke and Kenji will stay at the wisteria house for the night.

A few hours later, when it was time to go to bed, Zenitsu said;

Zenitsu: "Kenji,Tanjiro...Why are you traveling with a demon each?"