Koyanagi Sayaka

Sayaka is a young girl with bra-length black hair that has square bangs hanging over his forehead and blue eyes.

She wears a swimsuit top, short pants, long gloves with sleeves, and a collar with a plus symbol. In order to hide her identity, she would wear a hockey mask. she wears a G-string panty.

Sayaka was in love with a female teacher, who had moral doubts about their relationship and Sayaka ended up sharing with a friend, which led to the friend revealing it publicly and the teacher killing herself. After being betrayed, Sayaka started to have trust issues. Because of that, she had a very clear image of what she wanted and received her ability.

As Sayaka has a very clear idea of what she wants, she received an ability that would force the people that made contracts with her to keep her or her friends secrets. She ties a string of her hair around the person's neck, which soon becomes invisible and part of the body. And if the person reveals any secret about them, the string will tighten and kill the person.