Anko Uguisu

Age: 28
Birthday: October 31
Species: Human

Anko Uguisu is a private detective who specializes in cases involving vampires, and has made it her mission to kill all vampires. She is one of the only humans with knowledge of vampires and the secret on how to kill them.

Real Name: Kyouko Mejiro.

She was a member of a literature club and became Nazuna Nanakusa's first friend until her father was turned into a vampire, causing both parents to die and Kyouko to quit school and disappear.

Her father was turned into a vampire by Kiku Hoshimi who Anko has been investigating for years.
(Source: Yofukashi no Uta Wiki)