Hanabi Hyūga

is a member of the Hyuga Clan. She is the youngest daughter of Hiashi Hyuga, younger sister of Hinata Hyuga, and cousin of Neji Hyuga.

Background
Hanabi is Hinata Hyuga's younger sister. Her father considers her more talented than Hinata, but not as talented as Neji Hyuga, as he noted in the flashback in which Kurenai spoke with him about Hinata.

Chunin Exams
Hanabi watched Neji's match with her father, and was amazed to see that he had learned powerful secret techniques on his own. It was also indicated that she knew nothing about the failed attempt to kidnap Hinata that had resulted in Hizashi's death, mostly because she wasn't born at that time.

Anime Filer Arcs
Hanabi appears two more times in the anime, at the funeral of the Third Hokage and Tsunade's inauguration, standing with her cousin Neji and his teammate Tenten

Other Appearances
Hanabi is mentioned in a recap segment on House Hyuga, in which Neji briefly struggles to recall her name. In it, Neji refers to her as "Hanabi-san", in contrast to referring to Hiashi and Hinata as "-sama", possibly because she is neither the head of nor the heir to the household.