Setsuka

Appearance(Setsuka is a tall young woman with a curvaceous figure and pale skin. She has short pale cerulean hair that is put up into small curled buns. Her hair is held together by a black hair clip with a small yellow billiard ball labelled "9" attached to it, and a silver hairpin behind her head. She has plum eyes, with her right eye —the "devil's eye," as she would call it— closed most of the time. However, in one instance, its pupil is shown to have a target radar sign and emits light green aura. Setsuka wears a gray long-sleeved pinstripe shirt with a small Peter Pan collar and a black tie that is neatly secured with a silver clip on its middle. She dons a red O-neck vest over her shirt with gold trim and three buttons. There are also diamond patterns on the right side of her vest, alternating from deep red to khaki green, and leading onto the same pattern on her matching frilly jeans. A black belt with brass buckle is tied around her waist. She also wears sheer brown tights and red heels)

Talent(Setsuka is a highly skilled billiards player and tournament champion, possesses extensive knowledge of various techniques and game types. After losing her right eye due to an injury, she underwent an experimental eye transplant, acquiring her 'Devil's Eye'—a glowing blue eye that grants instant memorization when both eyes are open. However, this side effect often leaves her dizzy, as she perceives past and present simultaneously. During tournaments, she utilizes her Devil's Eye for perfect shots, earning her the title 'Super High School Level Billiards Player.' Despite her exceptional talent, Setsuka views billiards merely as a hobby.

Personality(Setsuka possesses a laid-back, optimistic personality that often leads her to treat others like children due to her mature appearance, earning her the nickname "big sis" in the killing game. Focused on uplifting everyone despite their dire circumstances, she organizes various mini-events, such as beach parties and concerts, to foster camaraderie. Setsuka serves as a moral support figure, particularly for emotionally vulnerable participants like Hibiki Otonokoji, offering comfort and planning group meet-ups. While she usually maintains a playful demeanor, she can also exhibit genuine concern and seriousness when the situation demands)

Past(Setsuka's childhood is largely unexplored, though she lived with her billiards pro father, who influenced her future career. Her earliest memory is of attending one of his tournaments when an accident resulted in severe facial injuries and a ruptured right eye. Despite her parents' objections, a doctor secretly performed an eye transplant, granting Setsuka the ability to record memories, though leaving both eyes open caused dizziness. As she honed her billiards skills, she won tournaments but was eventually banned for cheating. With her past behind her, she transitioned into a detective role, leveraging her unique eye to aid her investigations. Eventually, she was recruited by the Kisaragi Foundation to investigate the Voids, but was captured and forced into the Killing Game, making him forget the fact that he belongs to the Kisaragi Foundation.)