Gender: Female Occupation: Student at Utsunomiya Central High School Age: 17 Birthday: September 30th Favorite food: Garlic Disliked food: Tomato juice Guest's childhood friend. She has long black hair with gold inner highlights. She acts like a gyaru and is a high-energy girl. They became friends in early childhood before Guest knew she was a vampire, and they've been inseparable ever since. As a vampire, she drinks blood, but she isn't very good at it and often gets blood on her clothes. Every time it happens, she tries to come up with a different excuse. Thralls are created when Chiyui drinks the blood of someone she has romantic feelings for.