Hiashi Hyūga

is a shinobi from Konohagakure as well as the the current head of the Hyūga clan.

Background
Hiashi was born seconds before his twin brother Hizashi, making Hiashi the head of the Hyūga clan and Hizashi a member of the branch house, whose only purpose in life would be to protect members of the main house. Years later, when Neji was born, Hizashi became bitter that his son would never be able to reach his full potential like a member of the main house, causing him to be openly resentful of Hiashi and his daughter. Hiashi was also responsible for branding the family's curse seal on Neji's forehead, further straining the relationship between the two brothers. One day during Hinata's training, overwhelmed with resentment and anger, Hizashi gave Hinata a murderous glare, Hiashi sensed the killing intent and activated the curse seal on his younger brother, causing him intense pain. He told Hizashi to leave as he would no longer tolerate incidents like this. While in pain Hizashi tells Neji to never forget about his duties.

During a visit to Konoha by a Head Ninja of Kumogakure, who had come to the village to sign a peace treaty, a young Hinata was kidnapped. Hiashi however saved her, quickly killing her would-be kidnapper, only to discover that it was the Kumogakure ambassador. Kumogakure demanded Hiashi's head in return for the life he had taken, or risk resuming open warfare between the two villages. Konoha, wishing to avoid another conflict, was compelled to comply, but was not willing to fulfil Kumogakure's desire of getting to study the Byakugan. Their father suggested that Hizashi be used as a body double, since his cursed seal would seal off his Byakugan upon his death. Although Hiashi tried to find an alternative to this, Hizashi insisted, saying that he would finally get to choose his own fate (to make up for his wrongdoings against Hiashi), and save his brother's life. Before going to his death, he asked Hiashi to someday tell Neji about why he had made his decision.

Originally, Hiashi had trained Hinata to become the successor of the Hyūga clan. However, Hinata's lack of confidence ultimately led him to decide she was not worthy. He instead turned his attention to his younger daughter.

Personality
Hiashi's general personality is very stern and strict, as he assigns both his daughters arduous training, and rarely compliments their performance. This is especially true with Hinata; when she was assigned to Kurenai, he told her that he was unconcerned about the possibility that she would die, saying that the Hyūga clan had no use for a weak successor. In truth, it was not that he felt Hinata's talent or potential was weak, but her drive to succeed as the successor of the Hyūga clan. As the series progressed and she started to show her true dedication, he began to openly cheer her on. Hiashi was also very strict with his younger brother and nephew, and was willing to use the Cursed Seal to punish any disobedience. However, he truly cares for them as part of the family and his brother primarily seen in his hesitation to allow him to die to protect the secret of the Byakugan.

Hiashi has also shown at times to be lenient and is not as strictly devoted to following the main house's traditions, as seen when he started training Neji in the Hyūga clan's full arts in the hopes to end the growing rift within the clan, despite having been a taboo to passing down secret techniques of the main house to members of the branch family.

Appearance
Being an identical twin, Hiashi is a mirror image of his brother Hizashi with the exception of an unmarked forehead. He has long dark brown hair and featureless white eyes like all members of his clan. He normally wears very traditional, loose fitting robes with a cloak. When deployed to the Allied Shinobi Forces he donned the standard uniform of the Konoha shinobi, along with the forehead protector of the alliance.

Abilities
As the leader of the Hyūga Clan, Hiashi is undoubtedly a powerful shinobi. He's a master of the Gentle Fist, as well as a master of taijutsu in general. He also possesses the ability to use the Hyūga Main Family's Juinjutsu, showing some seal knowledge.

Byakugan
As a member of the Hyūga clan, Hiashi possesses the Byakugan, a dōjutsu kekkei genkai which grants him an almost 360° field of vision (with the exception of a small blind spot at the upper thoracic vertebrae), x-ray vision and the ability to see the chakra pathway system.

Taijutsu
Also, as the head of his clan, he is well-versed in all of his clan's secret techniques. While the full extent of his prowess remains unknown, during Orochimaru's invasion, Hiashi demonstrated tremendous skill by repelling in excess of twenty Oto and Suna ninja with the Eight Trigrams Palms Revolving Heaven technique. He also showed his great skill with the Gentle Fist when he killed the Kumogakure ambassador with a single strike to the chakra pathway system around his heart and left the fight unharmed. He can also use Eight Trigrams Empty Palm to hit targets seemingly out of his range.

Chūnin Exam Arc
Hiashi made his first début in Kurenai's flashback, when she was watching Hinata's and Neji's match in the preliminary matches of the Chūnin Exams. Hiashi debuted for the first time (in person) with Hanabi, watching Neji's match during the final rounds. He was amazed that Neji had been able to learn the main house's secret techniques by himself, but was disappointed by Neji's resentment of the main house, and his strong belief in fate. After Neji lost to Naruto, and seemed to have found himself at a crossroads in his life from Naruto's words, Hiashi decided to tell him about the circumstances surrounding Hizashi's death. Although Neji did not initially believe him, Hiashi's bowing to him for forgiveness showed him that it was true. In the anime, he also gives Neji a letter written by Hizashi, explaining the circumstances surrounding his death.

Invasion of Konoha Arc
Hiashi assisted in the defence of Konoha during the invasion by Sunagakure and Otogakure, repelling invaders. One of the invaders comments that there is only one of them and then they surround Hiashi who uses the Eight Trigrams Palms Revolving Heaven to get rid of them simultaneously. He then tells them that the Hyūga are the strongest in Konoha; a fact they would do well to remember.

Pre-Shippūden Filler Arcs
In the anime, Hiashi, realising separating the Hyūga clan into two houses was causing a huge rift in the clan, decided, as head of the clan, to try and mend this. He began training Neji regularly in their clan's full arts, something that was already considered a taboo by the rest of the main house (though the scene of him training with Neji was seen at the end of the Sasuke Retrieval Arc in the manga). His relationship with Hinata was shown improving, as he encouraged her to do her best after seeing her becoming more confident in herself.

Invasion of Pain Arc
Hiashi was noted to be away with Hanabi during Pain's attack on Konoha. He left Hinata's protection to Kō Hyūga during his absence.

Konoha History Arc
In the anime, it was later revealed that during the Invasion of Konoha a pair of Kumogakure ninja had tried to steal the Byakugan, kidnapping Hinata once again. After hearing about what happened from his father, he and Kō Hyūga set out to rescue Hinata. He arrives just as Neji is about to be struck fatally after trying to save Hinata. Hiashi blocks the attack using the Eight Trigrams Palms Revolving Heaven. Upon realising who he was the ninja attempts to flee, but he uses the Eight Trigrams Empty Palm to stop him. When Neji questions him on why he'd leave the battlefield to come after them, Hiashi tells Neji that Hinata is his precious daughter, and Neji, a precious memento of his late brother.

Shinobi World War Arc
When Hiashi returns to Konohagakure he is assigned to the First Division of the Allied Shinobi Forces under Darui's command. When his division takes up their post and Akatsuki's army starts to advance, Hiashi uses his Byakugan and sees not only the white Zetsu but the revived shinobi mixed in with them as well. A member of his clan turns his attention to the two o'clock direction where to his shock, he spots his brother, Dan and Asuma amongst the revived shinobi.

After confronting Hizashi who curses that though the branch family was supposed to protect the main house, he stood before him as an enemy. He then lamented that this must be his fate for defying the main house while he was alive. Remembering his brother's last words to him while he was alive, Hiashi tells him that there was no such fate and that Neji and Hinata were on the battlefield fighting to prove that not as branch house and main house members, but as two comrades protecting each other. With this, the two brothers begin battling. As the battle at the coast begins to end, Hiashi stands on Chōji's colossal fist which restrains his brother.

Trivia

 * Hiashi's name means 'daytime' or 'position of the sun'.
 * In Finally a clash! Jōnin vs. Genin!!, Hiashi stands behind his youngest daughter Hanabi Hyūga before the start of the event.
 * In English dub, the English voice actor for Hiashi also does the voice for his twin brother, Hizashi.

Quotes

 * (To the invading Suna and Oto ninja) "The Hyūga clan is the strongest in Konoha. Remember it well."
 * (To Neji) "Hinata is my precious daughter. And you are the precious memento of my late brother."
 * (To Hizashi) "There is no such fate! Your son and my daughter are out there fighting to prove it! This isn't about the branch house protecting the main house, it's about two comrades protecting each other!"