|Jafar says: Read my lips and come to grips with the reality!|
Yui Rio is a former NPC in Yandere Simulator. She was one of students at Akademi High School.
Yui had red hair and eyes of the same color but with a lighter shade. Her hair was worn in a ponytail to her right. In game files, her bust size was 0.5, and it was the smallest in the game. YandereDev said that in real life Yui would have the bust size AA, which is also the smallest bust size. On her right wrist, Yui had a red friendship bracelet. She also wore red panties, red stockings and a default uniform.
Yui had the "Evil" personality. Being the only one in the game who had this personality originally, and it means that if she witnessed murder alone, she praised Ayano and assured her that she would not tell anyone what she saw and then escaped from school. The next day, she would be pleased with Ayano, but she would not want to talk to her in order not to be involved in the murder. If she saw the corpses, she would not even be scared, she would just run and call the police. if she witnessed the murder, along with several other NPC, she would be one of four students who would stop the main character (probably only to not show her true nature to others).
This personality was later changed, as she was given the "Spiteful" personality, so she than only approved of the murders of those who bullied her and any students who were considered unpopular enough to be bullied. Otherwise, she would react with horror and would be disgusted with Ayano and try to tell people. This made her more of an anti-villain. She still took part in gossiping about Kokona and shaming her after her secret was revealed, and she would turn on any of her friends if they became unpopular enough to be bullied, showing joy with their deaths, so while she was not as cruel and heartless as previously, she was still far from a good person. She evidently hated unpopular students, and believed they deserved to die, while still hating bullies that picked on her. She would still help other students stop Ayano if there were three others present, even if the victim was a bully or unpopular student, likely just to hide her true nature.
Yui also hated cats. Furthermore, she was a perverted lesbian, evidenced by the fact that promo art showed her trying to grope Yuna's butt.