Blood type: AB
Project name: Black White
Affiliation: Thirteen PartyMedaka's Student Council, Zenkichi's Student CouncilMentality: AbnormalMinus (Ice Fire)Abnormality: Remodeling
Naze Youka is part of Class 13 and is the supervisor of the Flask Plan.
As Naze, she was once a classmate of Akune. Disgusted with the lack of dissatisfying elements in her life, the burdens of having a loving family and similarly extraordinary abilities, she became extremely stoic and driven to find something to make her miserable in life. Unable to achieve this goal, she ran away and erased her memories to become Youka Naze. Naze has little interest in the Flask Plan, using it only to further her scientific experiments on becoming normal. The only thing she truly values is her "best friend," Koga, the only person not to be intimidated by her overwhelming abnormality. Naze's abnormality appears to be analysis, similar to her brother, and an understanding of biology that allows her to remodel her body in short periods of time. Her preferred weapons are syringes. During her battle against Shibuki, she remodels herself and develops her own Minus Abnormality, "Ice Fire", which allows her to control her body temperature to freeze and burn objects at will.
Youka Naze's real name is Kujira Kurokami, the older sister of Medaka and the younger sister of Maguro. While attractive and possessing a strong resemblance to Medaka, she favors concealing her face behind bandages and embeds a knife in her forehead since she dislikes the attention her face attracts.
Despite her disagreeable personality and tendency to complain, she and Koga willingly aid the Student Council after Class 13 is disbanded. Naze volunteers to take the position of Vice-President in order to complete the necessary numbers to counter Kumagawa's challenge and threatens Zenkichi into allowing her to train him for the General Manager's battle. She comes to recognize Kikaijima, Akune, and Zenkichi as people who genuinely care about her and after defeating Shibuki in the Secretary's battle, Naze is able to reconcile with her younger sister.
Ten years later, Naze reunites with her friends on the tenth anniversary of Ajimu's disappearance. Changing in the Student Council office with the other women, she is startled by the sudden arrival of Zenkichi and Tsurubami. Naze is now the one who runs the Flask Plan, and explains to Zenkichi what the other members are now up to. She notes that half of Class -13 have disappeared however. Naze is one of the few who can still use her Abnormality. A flustered Naze holds Mogami as Kikaijima watches.