The Uchiha clan (うちは一族, Uchiha Ichizoku) was one of the four noble clans of Konohagakure. It was once almost extinct after the events of the clan massacre, however, Ryun Uchiha has restored the a branch of the clan by gathering its scattered members. Following the Fourth Shinobi World War, Sasuke Uchiha would restore Konohagakure's Uchiha clan through his own familial lines.
Before the Massacre
The Uchiha clan descended from the elder of the two sons of the Sage of the Six Paths. The elder brother inherited the Sage's "eyes", powerful chakra and spiritual abilities. When it came time for the Sage to choose a successor, he questioned the two on what course of action they would follow to bring order to the world. The elder believed that power was the way to bring peace, while the younger believed love was the way. The Sage favoured the ideal of the younger brother, and therefore designated the younger as his successor, causing the elder to be filled with jealousy and hate. From this hate came what Tobi calls the Curse of Hatred (憎しみの呪い, Nikushimi no Noroi). From the younger son descended the Senju clan who would be the eternal rivals of the Uchiha.
Before the founding of the ninja villages, the Uchiha were one of the many mercenary clans for hire. Because of their Sharingan, the Uchiha clan came to be known as one of the two strongest clans, the other being the Senju clan. Madara Uchiha was particularly powerful, and, upon attaining the Mangekyō Sharingan, he took control of the clan. Under his leadership the Uchiha grew stronger, conquering whatever clans they came upon, such that, whenever the Uchiha clan was hired for a job, the opposing side would hire the Senju, and vice versa.
The Senju clan, grew tired of the endless fighting, and approached the Uchiha clan with a peace treaty. Madara feared that an alliance would lead the Uchiha to ruin, but his clan disagreed, and he was forced to accept. The two clans came together to form Konoha, with Hashirama Senju, leader of the Senju Clan, being selected as Hokage. Madara believed that this was proof that the Uchiha would be made subservient to the Senju, but his clan saw this only as his attempt to rekindle the flames of war. They turned their backs on him, and he defected. Following Madara's betrayal, the Second Hokage gave the Uchiha control of the Konoha Military Police Force as a sign of trust. According to Tobi, this was really just a way of keeping the Uchiha in check and out of Konoha's governing affairs. Over the years, some Uchiha, such as Setsuna, have figured out this motive's true meaning, and tried to rebel against the village as Madara did, but they found that it was too late to make a difference, as the Senju had already completely suppressed the Uchiha.
Years later, after the Nine-Tails' Attack on Konoha, Konoha began to suspect that an Uchiha was behind the attack. Tobi claimed that the Uchiha were relocated to a corner of the village so that they could be more easily monitored. The Uchiha interpreted this as confirmation of what Madara had warned them of years earlier, and began to plan overthrowing the village. One Uchiha, Itachi, disagreed with the coup d'état, and informed Konoha's leadership of what the Uchiha were up to. The Third Hokage, Hiruzen Sarutobi, tried to negotiate for a more peaceful approach. This failed, and to prevent an uprising that would create another war, Itachi was ordered to wipe out the Uchiha.
Within one night, the entire clan was slaughtered with only one Uchiha was left alive: Itachi's younger brother, Sasuke. Sasuke would spend the next few years trying to avenge their family by killing Itachi, something Itachi had planned for from the very beginning. Once accomplishing this goal, Sasuke learned of Tobi's existence. Tobi told Sasuke about the Uchiha's history and why Itachi had wiped out the Uchiha, prompting Sasuke, with Tobi's help, to resolve to destroy Konoha.
In the decades following the massacre, the few Uchiha that survived wandered as missing-nin. One in particular, Ryun Uchiha, who was also the grandson of Madara Uchiha, became famous as a Yonkō and set out to rebuild the clan. Following the Fourth Great Shinobi World War, Ryun finally obtained enough power to begin setting this dream into motion. Following a battle with one of the leaders of a group of exiled Uchiha, Yoshitsune Uchiha, Ryun finally reestablished the clan and began seeking and recruiting new members.
The Uchiha were infamous for their especially strong and natural aptitude for anything combat-related, highly powerful chakra, and their proficiency in fire jutsu, having created several and using them more skillfully than any other. Their signature jutsu was the Fire Release: Great Fireball Technique. Clan members were not recognized as adults by the rest of the clan until they could successfully use this jutsu. The Uchiha were also highly known for their mastery of ninja tools. They themselves invented many shuriken techniques which required the use of thin metal wires, one example being the Windmill Triple Blades technique.
The Uchiha clan were most feared for their powerful Sharingan, a kekkei genkai which gives them the ability to see the "colors" of chakra, allowing them to analyze and copy their opponent's skills, along with a number of other abilities. Only a select few members of the Uchiha clan manifested the Sharingan. Due to their natural affinity for battle, and their proficiency with genjutsu, many ninjas considered it more tactically favorable to flee rather than face an Uchiha shinobi in one-on-one combat. Among the techniques granted by the Sharingan, the Izanagi is deemed to be forbidden, due to it rendering the user blind in exchange for temporarily turning their personal reality into an illusion. Though the clan was feared for their Sharingan, the eyes have also been transplanted into various characters outside the clan.
Madara discovered that, by the death of one's closest friend, the Sharingan could be taken to its next level: the Mangekyō Sharingan. It gave the user great power, but slowly deteriorated their eyesight. Only by taking the eyes of a sibling could one's vision be restored, a process that results in the creation of an Eternal Mangekyō Sharingan (永遠の万華鏡写輪眼, Eien no Mangekyō Sharingan). Itachi indicated that the intricacies of the Mangekyō Sharingan were only discovered after years of trial and error, implying that many Uchiha throughout history had made the attempt to gain the Mangekyō Sharingan.
A few select members of the clan, starting with Madara, had managed to awaken the Rinnegan, a legendary eye technique related to the Sage of the Six Paths. As it has been hinted that this was a natural evolution of the Eternal Mangekyō Sharingan, there remains the potential for others in possession of the latter to awaken the ability too. However, the exact requirements involved in this process have yet to be disclosed.
- According to Tobi, the Uchiha clan is destined to a life of revenge against their hated enemies, the Senju clan and Konohagakure. Although a few known members: Itachi, Obito and Shisui's ideals were the opposite of this.