Neji is a member of the Hyuga clan and possesses the Byakugan. He is a child prodigy and a genius. But as a member of a branch family of the Hyuga clan he is ineligible to learn their most secret techniques. Despite this however, he has managed to deduce their workings simply through observation, and has learned many of them.
Neji is highly proficient with the Gentle Fist style of hand-to-hand combat, which, in combination with the byakugan is used to attack an enemy's Chakra pathway system (the network of vessels which carry chakra), thus causing internal injury.
On the third birthday of Hinata (his cousin) when Neji was four years old, he was branded with the Main family's Juinjutsu which serves two purposes. The first is to seal their own byakugan ability when they die (shielding its secrets from enemies) and the second is to control the branch family members with the ability to destroy their brain cells with a secret hand seal.
A night soon after this, an incident occurred involving the main family's Hiashi (Neji's uncle and his father's twin brother) which could result in war for Konoha. To avoid this, Neji's father sacrificed himself. Neji mistakenly believed that the main branch had forced him to do so, and from this he developed a fierce grudge against them.
His feeling of oppression from the main family ruled in him adopting a fatalism philosophy – "fate is something determined at birth and no matter what one does, people can not escape their destiny". Neji attempts to condescend Naruto during their Chuunin exam match saying "that someone who is weak will always remain weak" but this fails and he goes on to be defeated. Naruto then suggests that if a "failure" like himself can change his destiny, a "genius" like Neji can, too.
After this match, and having been proven wrong, he abandons his philosophy. He also learns the truth about his father's sacrifice and is given the opportunity to resolve his estranged relationships with members of the main family by training with their leader (his uncle).
Neji is a member of Team Guy, along with Tenten and Rock Lee. During the two and a half year time skip between Part 1 and Part 2, when all the other rookie team members have advanced to Chuunin, Neji has gone one step further and advanced to Jounin – further emphasizing his abilities as a genius.
He is one of the best examples of the true talent which resides in Konoha, along with the likes of Naruto and Shikamaru. He trains constantly and vigorously. This is one character which describes your attention.