Ayako Hiiragi (平木 綾子 Hiragi Ayako) is Takahiro Mizuno's cousin and a school physician at Winford Academy, at night and during weekends she run a cafe called "Tart Time" where Mio Kisaki and Noel Marres Ascot works as part-timers and where Akane Ryuuzouji would often hang-out. The place also functions as a living quarters both for her and Takahiro. She like teasing Takahiro and Mio a lot.
- The name Ayako means "color" (彩), "design" (綾) or "brilliant fabric design, kimono design" (絢) (aya) and "child" (子) (ko).
- Ayako's surname Hiiragi means "flat" (平) (hiira) and "tree, wood" (木) (ki/gi).