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
As the younger sibling, there is a possibility she will be placed in the Branch Family(Known as the Cadet Branch in the manga) and receive a Cursed Seal, once the next heir turns three. However, because her father felt that Hanabi was a more suitable heiress than Hinata, and because there has been several changes in the way the Hyuga family works, it is possible she might be exempt from this. Since she is a girl, it is also possible she was never meant to have a Cursed Seal in the first place, as Japanese tradition usually only allows men to start a branch family.

Chunin Exam arc
Hanabi watched Neji's match against Naruto during the final round of the Chunin Exams 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, as she did not know how her father could still be alive after the Land of Lightning demanded his death.

Anime Fillers
Hanabi appeared three more times in the anime; when Kurenai Yuhi came to talk about having Hinata join Team 8, at the funeral of the Third Hokage, and at Tsunade's inauguration, standing with her cousin Neji and his teammate Tenten.

Pain Invasion Arc
Although she didn't make an actual appearance, Hanabi was noted to be away with her father during Pain's attack on Konoha.

Trivia

 * Hanabi's name means "fireworks".
 * Hanabi also appears as a playable character in Naruto: Ultimate Ninja 3 and Naruto Shippuden: Ultimate Ninja 4.