|Japanese name:||名瀬 夭歌|
|Nickname:||Black White, Kujira Kurokami|
Blood Type: AB
Youka Naze, real name Kujira Kurokami, is a junior of Class 13 and a former member of the Flask Plan's Thirteen Party. Her project name is Black White. She later becomes the vice-president of Zenkichi Hitoyoshi's Student Council. She is the middle child of Kajiki Kurokami, younger than Maguro Kurokami, but older than Medaka Kurokami.
When she was young she believed that the best geniuses came from a hell-like environment and she grew up hating her great life because of it. She is a extreme stoic (doesn't show her true emotions) and likes to study. She is intelligent about Biology which allows her to modify bodies. Even thought she had a great life, she wanted to live in a deeper hell so she ran away from home and changed her name. Because she wanted it, she was bullied in Class 11 which is where she met Itami Koga who she loves as a friend. However, she does seem to have a slight weakness of boasting, shown during the fight between Zenkichi and Misogi Kumagawa where she repeatedly extols the magnificence of the person who trained Zenkichi for the fight (i.e. herself) and comparing the result as being far more successful then what her brother could have achieved. She does however exhibit some personality traits of a Minus: when provided with the opportunity, she nearly betrayed her comrades to help Kumagawa, before remembering that she cared about them. Recently, she has also taken up Medaka's habit of sending Maguro flying into a wall every time he hugs her.
Voiced by: Miyuki Sawashiro