Toyosu Aiko

Weak spot: Anywhere she is bit on
Fetish: Watching other girls being raped

Kou's childhood friend who has however distanced herself from him. She is easily pushed around and hates the fact that she's extremely serious. Aiko also compares herself often to her older sister Midori, who is good at everything, which in turn gets Aiko very depressed and feel inferior to her. However, she does also have a secret: she is addicted to masturbating.