Hino Aoi (日野葵 Hino Aoi) is one of the main Cures in Happiness Pretty Cure. She is very kind and smart. She is the school president. Her theme color is blue. Her Pretty Cure alter ego is Cure Crystal (キュアクリスタル Kyuakurisutaru).
Aoi has chest-length dark blue hair and sky blue eyes. Casually she wears a pearl blue dress with light blue lining and blue ribbon. A band of navy wraps beneath the chest, and worn over this is a milk blue bolero. Included are boots matching the colors or her outfit. Her school uniform is worn normally. As Cure Crystal her eyes and hair gets lighter.
When she was first introduced, she seems like an elegant and quiet girl, but also quite understanding. She is modest and hates to put anyone through trouble, going so far as to initially refuse any help. Aoi is also quite calm and patient, not even appearing phased as the others told her about Pretty Cure, and she tried to politely spare their feelings when refusing their request.