The Mangekyō Sharingan:
(万華鏡写輪眼; Literally meaning "Kaleidoscope Copy Wheel Eye"), noted to be the "heavenly eyes that see the truth of all of creation without obstruction" (天壌の理を掌握せし瞳, tenjō no kotowari wo shōaku seshi hitomi), is an advanced form of theSharingan that has only been activated by a handful of Uchiha. It was also awakened by Kakashi Hatake — a non-Uchiha.
The Mangekyō Sharingan is awakened through the trauma experienced from the death of a person very close to the Sharingan user. With the user normally having to witness or experience this first hand, Uchiha throughout history have killed those closest to them in order to expedite this process. To obtain the Mangekyō Sharingan, one mustfeel the emotion of losing a friend or family, as merely killing them or watching them die will not activate it.
It is distinguished from a normal Sharingan by its appearance, which changes the form of the tomoe seal. Unlike the Sharingan, the appearance of the Mangekyō Sharingan differs from user to user with all known wielders of the dōjutsu having eyes that resemble variations of pinwheels; one variation is known as the "Straight Tomoe" (直巴, Choku Tomoe), which seems to grant the user fluidity in their movements when fighting. It has been used to cast genjutsu on tailed beasts, even as fearsome as Kurama, the Nine-Tailed Demon Fox, a feat only Madara and Obito Uchiha have displayed thus far.
Over time, use of the Mangekyō Sharingan's techniques deteriorates the user's eyesight to the point of blindness, a harsh fate for those that have grown accustomed to the power and visual acuity it affords. Only by transplanting the eyes of another Uchiha can they hope to regain their sight and ocular powers. If the transplanted eyes happen to be the Mangekyō Sharingan of an Uchiha with strong blood ties with the recipient — ideally a sibling — the likelihood of compatibility is increased, resulting in the creation of an Eternal Mangekyō Sharingan (永遠の万華鏡写輪眼, Eien no Mangekyō Sharingan). This process, which took at least several days for a complete recovery as seen in Sasuke's case, not only permanently restores the recipient's eyesight, but also bolsters their own ocular power with that of the donor's. This is signified by the intertwined appearance of their Mangekyō Sharingan's tomoe seals, with traits of the donor's tomoe merging with those of the eyes' new host. Due to the strict compatibility issues and the Mangekyō Sharingan's rarity, not everyone can gain these benefits by transplanting the eyes of just any Uchiha, which has been the cause of many fruitless sacrifices throughout the Uchiha clan's history. Thus far, only Madara and Sasuke are known to have been successful in this endeavour.
Madara was able to change his Eternal Mangekyō Sharingan into the Rinnegan after implanting the DNA of Hashirama Senju into himself, though the dōjutsu only awakened years after the implant, when Madara's natural lifespan was almost over.
Itachi Uchiha gained the Mangekyō Sharingan by aiding his best friend, Shisui, in killing himself. With the Mangekyō Sharingan, Itachi was able to use at least three powerful techniques. With his "left Mangekyō" he could use Tsukuyomi, an extremely powerful genjutsu that allowed him to distort the victim's perception of time, torturing their psyche for what seemed like days in a matter of seconds. With his "right Mangekyō" he could use Amaterasu, a ninjutsu which creates virtually-inextinguishable black flames at the user's focal point that continue to burn until the target is reduced to ash. The last of these known techniques was Susanoo, which allowed Itachi to summon a massive ethereal warrior. This entity fights on behalf of Itachi and shields him from most attacks. According to Zetsu, when it is combined with the Yata Mirror and Sword of Totsuka it essentially made Itachi invincible. Itachi's Susanoo has three forms which it goes through: an incomplete skeletal form, a complete warrior-like form and a final form that resembles a yamabushi.
Use of the Mangekyō Sharingan put a great strain on Itachi's body and would quickly deplete his chakra reserves to the point that after using it three times in a day, he deactivated his eyes to their normal state. A clone containing 30% of his chakra couldn't use it once. By the time he battled Sasuke, his sight had been reduced to a large blur, yet having resolved himself to dying at the hands of his brother, pushed past this limitation and used his Mangekyō Sharingan more than three times as well as other techniques. After being reincarnated by the Impure World Reincarnation technique, Itachi was able to use the Mangekyō Sharingan for extended periods of time without complaints of physical ailments, or deteriorating vision. Some time after his death, Sasuke eventually took Itachi's Mangekyō Sharingan as his own, granting the former an Eternal Mangekyō Sharingan.
(万華鏡写輪眼; Literally meaning "Kaleidoscope Copy Wheel Eye"), noted to be the "heavenly eyes that see the truth of all of creation without obstruction" (天壌の理を掌握せし瞳, tenjō no kotowari wo shōaku seshi hitomi), is an advanced form of theSharingan that has only been activated by a handful of Uchiha. It was also awakened by Kakashi Hatake — a non-Uchiha.
The Mangekyō Sharingan is awakened through the trauma experienced from the death of a person very close to the Sharingan user. With the user normally having to witness or experience this first hand, Uchiha throughout history have killed those closest to them in order to expedite this process. To obtain the Mangekyō Sharingan, one mustfeel the emotion of losing a friend or family, as merely killing them or watching them die will not activate it.
It is distinguished from a normal Sharingan by its appearance, which changes the form of the tomoe seal. Unlike the Sharingan, the appearance of the Mangekyō Sharingan differs from user to user with all known wielders of the dōjutsu having eyes that resemble variations of pinwheels; one variation is known as the "Straight Tomoe" (直巴, Choku Tomoe), which seems to grant the user fluidity in their movements when fighting. It has been used to cast genjutsu on tailed beasts, even as fearsome as Kurama, the Nine-Tailed Demon Fox, a feat only Madara and Obito Uchiha have displayed thus far.
Over time, use of the Mangekyō Sharingan's techniques deteriorates the user's eyesight to the point of blindness, a harsh fate for those that have grown accustomed to the power and visual acuity it affords. Only by transplanting the eyes of another Uchiha can they hope to regain their sight and ocular powers. If the transplanted eyes happen to be the Mangekyō Sharingan of an Uchiha with strong blood ties with the recipient — ideally a sibling — the likelihood of compatibility is increased, resulting in the creation of an Eternal Mangekyō Sharingan (永遠の万華鏡写輪眼, Eien no Mangekyō Sharingan). This process, which took at least several days for a complete recovery as seen in Sasuke's case, not only permanently restores the recipient's eyesight, but also bolsters their own ocular power with that of the donor's. This is signified by the intertwined appearance of their Mangekyō Sharingan's tomoe seals, with traits of the donor's tomoe merging with those of the eyes' new host. Due to the strict compatibility issues and the Mangekyō Sharingan's rarity, not everyone can gain these benefits by transplanting the eyes of just any Uchiha, which has been the cause of many fruitless sacrifices throughout the Uchiha clan's history. Thus far, only Madara and Sasuke are known to have been successful in this endeavour.
Madara was able to change his Eternal Mangekyō Sharingan into the Rinnegan after implanting the DNA of Hashirama Senju into himself, though the dōjutsu only awakened years after the implant, when Madara's natural lifespan was almost over.
Itachi Uchiha gained the Mangekyō Sharingan by aiding his best friend, Shisui, in killing himself. With the Mangekyō Sharingan, Itachi was able to use at least three powerful techniques. With his "left Mangekyō" he could use Tsukuyomi, an extremely powerful genjutsu that allowed him to distort the victim's perception of time, torturing their psyche for what seemed like days in a matter of seconds. With his "right Mangekyō" he could use Amaterasu, a ninjutsu which creates virtually-inextinguishable black flames at the user's focal point that continue to burn until the target is reduced to ash. The last of these known techniques was Susanoo, which allowed Itachi to summon a massive ethereal warrior. This entity fights on behalf of Itachi and shields him from most attacks. According to Zetsu, when it is combined with the Yata Mirror and Sword of Totsuka it essentially made Itachi invincible. Itachi's Susanoo has three forms which it goes through: an incomplete skeletal form, a complete warrior-like form and a final form that resembles a yamabushi.
Use of the Mangekyō Sharingan put a great strain on Itachi's body and would quickly deplete his chakra reserves to the point that after using it three times in a day, he deactivated his eyes to their normal state. A clone containing 30% of his chakra couldn't use it once. By the time he battled Sasuke, his sight had been reduced to a large blur, yet having resolved himself to dying at the hands of his brother, pushed past this limitation and used his Mangekyō Sharingan more than three times as well as other techniques. After being reincarnated by the Impure World Reincarnation technique, Itachi was able to use the Mangekyō Sharingan for extended periods of time without complaints of physical ailments, or deteriorating vision. Some time after his death, Sasuke eventually took Itachi's Mangekyō Sharingan as his own, granting the former an Eternal Mangekyō Sharingan.