Erio Touwa is a central character in the anime series 'Denpa Onna to Seishun Otoko.' She is the mysterious, blue-haired cousin of the protagonist, Makoto Niwa. Erio is known for her eccentric behavior, often wrapping herself in a futon and claiming to be an alien. Her unusual actions and background become a focal point in the story, as Makoto gradually tries to help her reintegrate into society and uncover the truth behind her past. Erio's unique personality and struggles greatly influence the series' themes of adolescence and identity.