Nozomi

Manga: Nozomi (ノゾミ ?) is a 15-17 year old soft-spoken and shy friend of Yuka who would have been introduced around episode 6-7, but only appears in the manga for unknown reasons, although some theories are that they couldn't find a fitting voice for her, or that they didn't know what to do with her since the manga was still ongoing. She has a psychological bladder problem because of her father frequently physically abusing her when she was a child for wanting to become a singer and therefore wears diapers. Kouta first encounters her while walking to the store (not realising they both know Yuka), and both are embarrassed when the wind blows her skirt up. They later meet at the restaurant and Nozomi is revealed to have a great talent for singing. Nozomi is the person who sings the song "Elfenlied", while teaching Nyū how to sing. (Source: Manga & Wikipedia)