Natsuki Yukawa

Yukawa Natsuki (湯川 夏希) is one of the heroines of Reijou Seisui Gakuen. She is a girl with an interest in gothic lolita and the occult, she was student council president the year before and her academic abilities rival Mana's. She use to have a lesbian relationship with Mana but it is a black history she rather not talk about.

She interacts with the protagonist with a chuuni behavior but it is all just an act so that she can hide and forget about her love for Mana. Because her father is the director of the school none of the teachers interfere with her, so she wanders the school by herself playing detective while keeping the bare minimum attendance record. While she provokes the protagonist with sexual deeds she is easily caught up in pleasure but insist that it is all just an act.

Personality
She is very bright and cheerful, but also smart and manipulative. She usually interacts with other people with chuuni behavior.

Story
In the beginning, Natsuki tease Tetsuya that he are a pervert. Tetsuya suddenly took an interest in her stated that she is "made to be keenly felt that it was a distinctly different existence. There's even something indescribable and eerie." and he really wants to do erotic things with her.

Natsuki later confronted by Tetsuya who tries to make friends with her, due to her intelligence, she easily knows about Tetsuya's intention that he wants to do naughty things by making Natsuki, Nagisa-chan, And Mana-chan sex slaves.

However, Natsuki states that she was okay with it if she's the only one, much to Tetsuya's surprise. Natsuki use Tetsiya's phone to take the picture of her naked body, Tetsuya asks her what do she want, Natsuki says that she want him to help her destroy her boring daily life, and wants him to be her assistance. She asks if Tetsuya fell in love with her, which he replies that he actually, fell in hate, and will humiliated her. Natsuki laughs and said that she also likes that too, and invite him to be her assistance. Tetsuya accepts because he wants to make her his sex slave and use her for other purpose.

Natsuki provokes him many times, and Tetsuya really likes it. So he began to harass her back, which Natsuki slowly falling to pleasure. Tetsuya still don't understands Natuki's intentions, but he decided to make Natsuki herself aware of her pleasure and to arouse her sense of shame. Natsuki herself slowly aware of her pleasure, and starts to have a feeling for him.

She accepts to be his sex slave (just) for fun, and Tetsuya decided to properly train her.

Natsuki challenge Tetsuya that if he can guess what she's hiding, she'll tell him all about it, Tetsuya gladly accepts.

Natsuki later revealed that she was in relationship with Mana in the past, and still lover her, cause Tetsuya to jealous.

Natsuki tricks Tetsuya, and going to send him to police but Tetsuya tricks her back by saying that he fell in love with her, Natsuki was convinced and believes him, and becomes his real sex slave.

Trivia

 * Natsuki normally use "watashi", but will change to "boku" when she's in detective mode.
 * Tetsuya really likes this changes.
 * Natusuki is the only girl that Tetsuya admits that he fell in love with her at first sight.