Shizuku  

, 静水久

Shizuku is a Mizuchi (Water dragon demon) who appears as a green, short-haired small girl with a snake tongue that can stretch far, similar to a chameleon's, and she can breathe underwater. She usually has a stoic expression and is always soaked in water. Shizuku first encounters Yūto at the river where she warns him about continuing his demon slayer heritage, which could lead to her killing him. To prove this, she invites herself to live in Yūto's house and develops romantic feelings for him.