Anju is Karin's younger sister and she absolutely loves her, close to the point of obsession. She will do anything for Karin. She has not quite awakened as a vampire, causing her to be somewhat sensitive to the sun, and resulting in her only attending school on overcast days. However, she does have an amazing control over bats despite this.

Anju is very reserved, speaking in a quiet manner and wears a Gothic Lolita attire. Boogie-kun is her companion, whom she carries around and is her favorite of her dolls, something she enjoys collecting.

In the anime, Anju's blood preference is jealousy when she awakens. In the manga, it's loneliness.