Mangekyō Sharingan

The is a heightened form of Sharingan. The Mangekyō Sharingan gives the user access to powerful and forbidden techniques. The Mangekyō Sharingan is distinguished from a normal Sharingan through its appearance, which changes the form of the tomoe seal. Unlike in the case of the Sharingan, the appearance of the Mangekyō Sharingan differs from user to user; Kakashi Hatake's and Itachi Uchiha's both resemble pinwheels, Madara Uchiha's and his brother, Izuna's look more like a detailed form of the basic three-tomoe Sharingan, and Sasuke Uchiha's looks like three intersecting ellipses.

To acquire the Mangekyō Sharingan, the person closest to the Sharingan user must die and the emotion of the loss is responsible for unlocking it. To expedite this occurrence, most Uchiha throughout history have killed their closest friends or family members in order to meet this criteria, though, how Kakashi gained his Mangekyō Sharingan has yet to be explained. (It is interesting to note that in order to obtain the Mangekyō Sharingan, one must feel the emotion of losing a friend, the act of killing them or watching them die alone will not activate it. This is seen with Sasuke and his Mangekyō.)

Over time, use of the Mangekyō Sharingan's techniques deteriorates the user's eyesight to the point of blindness. Only by taking and transplanting the eyes of another who also wields the Mangekyō Sharingan can the vision be restored, a process that results in the creation of the. Not only does this process restore one's eyesight, but it also gives the person greater power. There are only three known living shinobi left who possess the Mangekyō Sharingan: Kakashi Hatake, Madara Uchiha, and Sasuke Uchiha.

Itachi Uchiha
Itachi Uchiha gained the Mangekyō Sharingan by killing his best friend, Shisui. With the Mangekyō Sharingan, Itachi was able to use at least three powerful jutsu. The first was Tsukuyomi, an extremely powerful genjutsu that allowed him to torture opponents for what seemed like days in a matter of seconds. The second technique was Amaterasu, a substantially potent 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 techniques was Susanoo, which allowed Itachi to summon a massive ethereal warrior. This entity fights on behalf of Itachi and shields him from all attacks, rendering Itachi essentially invincible.

All of these techniques use massive amounts of Itachi's chakra and, in addition to damaging his eyesight, put a great deal of strain in his body. During his final battle against Sasuke, Itachi's eyes were even shown bleeding after using the Mangekyō. He told his brother that he wanted to take his eyes so that he can restore his eyesight and gain more power. During the resulting battle, Zetsu noted that Itachi's "Left Mangekyō" possessed the Tsukuyomi, while the "Right Mangekyō" possessed the Amaterasu.

Itachi's eyes are later mentioned in a conversation between Sasuke and Madara in which the former reveals that he wants a transplant of his brother's eyes in order to obtain the Eternal Mangekyō Sharingan and combat Naruto Uzumaki. The eyes are then transplanted into Sasuke successfully, and he felt his brother's powers flowing into him.

Kakashi Hatake
Kakashi Hatake developed his own Mangekyō Sharingan during the time-skip. With his Mangekyō Sharingan, Kakashi mastered a technique that creates a localized inter-dimensional space-time ninjutsu called Kamui, allowing him to send a target to another dimension. The attack requires considerable effort to aim precisely and appeared to leave Kakashi's chakra significantly drained; he collapses after using the technique three times even at full strength in a single day. How he awakened his Mangekyō Sharingan remains unknown, as he stated that everyone close to him was dead.

Madara Uchiha
Madara Uchiha is the first Uchiha to have awakened the Mangekyō Sharingan. His Mangekyō took the form of a ring with three circular holes in it. He eventually grew blind from overusing it, and only by taking his younger brother Izuna's eyes did he regain his sight. This also gave him an "Eternal" Mangekyō Sharingan that gave him great power. His Eternal Mangekyō Sharingan looks identical in appearance to Madara's first Mangekyō combined with Izuna's Mangekyō.

Madara, posing as Tobi, has shown using an unnamed space/time ninjutsu which makes him nearly invulnerable and allows him to teleport to different places at will very quickly, but it's unclear if this is a result of his Mangekyō Sharingan. He is also able to use a variation of this ability which bears some similarity to Kamui, allows him to teleport others to another location/dimension, and later summon them at will. It is unclear if either jutsu are from his Mangekyō Sharingan. While it is unknown what other (if any) Mangekyō jutsu he may have, Madara has demonstrated detailed knowledge and understanding for each Mangekyō jutsu. Also in the past, Madara was able to use his Mangekyō Sharingan to control the Nine-Tailed Demon Fox like a pet. However, it has yet to be shown in the present.

Izuna Uchiha
Izuna Uchiha acquired his Mangekyō Sharingan soon after Madara did. His took the appearance of three bars stretching out of his pupil. Madara later took Izuna's eyes to regain his lost vision. In Madara's story, however, Izuna volunteered to give him his eyes for the clan's sake.

Sasuke Uchiha
Sasuke Uchiha awakened his Mangekyō Sharingan after he realized the truth about his brother Itachi and his sacrifices for Konoha and Sasuke. He was aggrieved to accept the fact that he himself had ended Itachi's life, and in his grief, he awakens his Mangekyō Sharingan. Sasuke's Mangekyō takes the appearance of three intersecting ellipses. Unlike other Sharingan, which have a black design and red background, Sasuke's Mangekyō is the first one that is shown to have a red design and a black background.

The first ability Sasuke has displayed using the Mangekyō is Tsukuyomi, capable of breaking the target's will, however Danzō Shimura stated that Sasuke's skill is not near the skill of Itachi's, saying that Itachi was able to alter the victim's perception of time at his whim, and that Sasuke is as far below Itachi as the ground is from the sky. As with Itachi's version, it is powerful enough to break down the will of the intended victim, and even cause paralysis. The second ability, was Amaterasu, which Itachi implanted within his eyes before his death. When Sasuke first used it unintentionally against Madara, his eyes assumed the appearance of Itachi's Mangekyō Sharingan. When he later used it on his own, they took the form of his own Mangekyō Sharingan. Various characters have implied that his skill with Amaterasu surpasses Itachi's, as he is able to control the flames with his right eye, although both can extinguish them. He suffers from the same drawbacks from using it as Itachi did, as his eye is strained to the point of bleeding, as well as his eyesight gradually began to deteriorate.

Sasuke has displayed the ability to use Susanoo, which he can even partially manifest to suit the situation, such as using a ribcage for easy defense, or making an arm appear, which he used in the fight against Danzō. At first, he used an incomplete version of Susanoo, but later during the fight with Danzō, he perfected it, creating a Susanoo with flesh, a real face, and a bow and arrow. Later, when fighting Kakashi, Sasuke's Susanoo also briefly took the form similar to that of Itachi's, before his deteriorating eye sight dissolved the jutsu.

Unlike Itachi, Sasuke's Amaterasu (ninjutsu) comes from his left eye, and his Tsukuyomi (genjutsu) comes from his right eye, along with his ability to manipulate and extinguish the black flames.

Due to the rapid deterioration of eyesight from overuse of his Mangekyō, Sasuke has opted to have Itachi's eyes transplanted. It is later revealed that the transplant was a success, although his eyes have yet to be seen, as they are wrapped in bandages.

=
)