Rio Futaba

Rio, who hosts her school's Science Club at one of its laboratories, comes across as a well-articulated and intelligent young woman with extensive knowledge of chemistry and quantum physics, albeit at the cost of sociability, as only one other person has ever frequented her club. She is often seen using lab apparatus to make coffee.

Rio is often blunt and to-the-point; she has a sharp sense of humor and is even more sarcastic and straightforward than Sakuta. Before experiencing it herself, she was unwilling to believe the existence of Adolescence Syndrome, but she did acknowledge the abnormal phenomenon it induces and connects them with various scientific theories and principles.

Despite her straightforwardness and somewhat cold exterior, she's still a kind, helpful and supportive person, consistently helping Sakuta in solving Puberty Syndrome cases. She's also more sensitive and insecure than she lets on, as seen in her arc where she deals with the self-consciousness about her early developed body.

Rio is dedicated to the Science Club such that she even goes to school during summer break in order to keep the Science Club afloat. The summer break is also when Rio's case of Adolescence Syndrome happens; both versions of Rio act almost similarly except for one difference - one of the Rio's seeks validation of her body and thus frequently posts pictures of them online.