The student council president at Millennium Science School. Cold, unsociable, calculating and rather scrupulous, cares more about objective facts than emotions, never letting them change her mind, making a lot of students find her to be terrifying, but she doesn't bother by their opinion. She's also very determined when it comes to reaching her goals, even breaking the rules if she has to. Rio has red eyes, long black hair and a body way too mature for a student.