Mangekyō Sharingan

The is an advanced form of the Sharingan that has only been activated by a handful of Uchiha. They are noted to be the.

Overview
A Mangekyō Sharingan is distinguished from a normal Sharingan by its appearance, which changes the form of the tomoe seal. The exact design differs for each user, though all resemble pinwheels. It is initially awakened by the trauma suffered from witnessing the death of someone close to the user. Uchiha have historically misunderstood this criteria as the user needing to be responsible for the person's death, and for that reason they developed the practice of killing their closest friends in order to gain the Mangekyō Sharingan. Obito's Mangekyō activated immediately after his trauma, whereas, in Naruto Jinraiden, Sasuke's Mangekyō didn't activate until several weeks afterwards.

The Mangekyō Sharingan retains all of the Sharingan's generic abilities, such as casting genjutsu and the ability to distinguish chakra. In addition to these, the Mangekyō grants powerful abilities that differ from user to user, though abilities may be similar in nature; both Sasuke and Itachi have access to Amaterasu's flames, though the extent to which they can use them differ. The abilities of a Mangekyō Sharingan may not even be the same for both of a single user's eyes, as Itachi has Amaterasu in one eye and Tsukuyomi in another. Once a user awakens the Mangekyō in both eyes, or the ability of both of their eyes, they are able to perform Susanoo.

The Mangekyō Sharingan's abilities drain a considerable amount of chakra when performed. Its usage and activity also place a great strain on the user themselves, wearing at the user's body and causing deterioration to their vision until eventually over-usage leaves them blind. Their vision can be restored by receiving the transplanted Mangekyō of an Uchiha with strong blood ties — ideally a sibling — thus awakening so-called. The Eternal Mangekyō merge the designs of the transplanter and the transplantee's original Mangekyō. Their Mangekyō-based abilities are made stronger and they no longer suffer any negative side-effects from the usage. According to Madara, the Eternal Mangekyō Sharingan is proof an Uchiha continues to seek something despite experiencing great losses. Should the eyes evolve to this state, the user will retain all their previous techniques from their original eyes. In addition to the unique techniques, the form of Madara's and Sasuke's Eternal Mangekyō Sharingan grants them fluidity in their movements when fighting.

As with any dōjutsu, Mangekyō Sharingan can be transplanted into non-Uchiha, granting them all its abilities albeit with steeper chakra demands. Abilities of a Mangekyō Sharingan can also be programmed to activate under certain circumstances, either within the user's own eyes or in a target of the user's choosing; this programming remains even after death.

The Mangekyō Sharingan also grants its user the ability to read and decode the Uchiha Clan's Stone Tablet. According to Obito, the Mangekyō Sharingan can decode it more than the Sharingan, but less than the Rinnegan.

Itachi Uchiha
Itachi Uchiha awakened his Mangekyō Sharingan after witnessing the suicide of his best friend, Shisui Uchiha, shortly before the Uchiha Clan Downfall. With his left Mangekyō he can use Tsukuyomi, an extremely powerful genjutsu that distorts the victim's perception of time. With his right Mangekyō he can use Amaterasu, creating inextinguishable black flames at the user's focal point. Because he awakened both his Mangekyō, he can use Susanoo. Use of the Mangekyō is particularly debilitating for Itachi, such that after using it three times in one day he can no longer keep even his normal Sharingan active. Some time after Itachi's death, desiring the power to kill Naruto, Sasuke Uchiha had Itachi's eyes transplanted into him.

Obito Uchiha
Obito Uchiha awakened his Mangekyō Sharingan after the death of Rin Nohara during the Third Shinobi World War; Obito himself only had his right eye at the time, but the event caused his Mangekyō to simultaneously awaken in Kakashi Hatake, who wielded Obito's left eye. Both eyes have access to Kamui, able to teleport targets to and from Kamui's Dimension though in different manners. The right eye is able to use close-range Kamui, teleporting the user or those they're in contact with. By teleporting only parts of their body there, they can in effect seamlessly pass through other matter. The left eye is able to use long-range Kamui, creating a barrier around a target that teleports them. The left eye can also target the user themselves. During the Fourth Shinobi World War, it was discovered that each eye is impervious against the others' Kamui.

Madara Uchiha steals Kakashi's eye in order to pursue Obito to Kamui's dimension. There, he exchanges the eye for Obito's Rinnegan, returning both eyes to their original owner, who was currently possessed by Black Zetsu. During this brief period, Black Zetsu also gained access to both Sharingan powers. After Obito was freed from Black Zetsu's control, he uses them in combination effectively thereafter, but the eyes are destroyed when he is killed by Kaguya Ōtsutsuki's All-Killing Ash Bones. His spirit briefly returns to the living plane and inhabits Kakashi, giving him both Mangekyō's with their respective abilities and, by extension, Susanoo.

Madara Uchiha
Madara Uchiha was the first Uchiha to awaken the Mangekyō Sharingan. It's not known what the individual abilities of each of his eyes were, but he was able to use Susanoo. When Madara's over-usage of his Mangekyō during the Warring States Period left him blind, this prompted his brother, Izuna Uchiha, to bequeath Madara his eyes on his deathbed for the sake of preserving the Uchiha, thus granting Madara the Eternal Mangekyō Sharingan. The straight tomoe of his Eternal Mangekyō Sharingan granted him fluidity in his movements when fighting.

Towards the end of his life, Madara was able to evolve his eyes into Rinnegan, which he transplanted to Nagato when Nagato was a child without anybody ever knowing. The eyes eventually found their way back to Madara after he is revived.

Izuna Uchiha
Izuna Uchiha awakened his Mangekyō Sharingan shortly after Madara did. It's not known what the individual abilities of each of his eyes were. Before he died, Izuna entrusted his eyes to Madara in order to restore his vision and thus protect the Uchiha from extinction. Despite Izuna giving the eyes willingly, Madara is popularly believed to have taken the eyes against Izuna's will.

Sasuke Uchiha
Sasuke Uchiha awakened his Mangekyō Sharingan after the death of his older brother, Itachi Uchiha. With his left Mangekyō he can cast Amaterasu. With his right Mangekyō he can shape the flames or extinguish them. Because he awakened both of his Mangekyō, he can use Susanoo. Sasuke is initially reluctant to transplant Itachi's eyes and gain the Eternal Mangekyō Sharingan, claiming that his views were different from Itachi's. Later, he decided he needs the increase of strength in order to kill Naruto Uzumaki. The straight tomoe of his Eternal Mangekyō Sharingan grant him fluidity in his movements when fighting.

After acquiring the half of Hagoromo's chakra, Sasuke's left Mangekyō Sharingan evolved further into a unique version of the Rinnegan.

Shisui Uchiha
 Shisui Uchiha awakened his Mangekyō Sharingan after he "allowed his friend and rival to die". With each of his eyes he could use Kotoamatsukami, a powerful genjutsu that manipulates a target's thoughts completely without any, including the target, having the slightest idea that they were being controlled. However, this technique can't be used with the same eye again until after a prolonged period of time. In the anime, awakening the Mangekyō Sharingan in both eyes allowed him to use Susanoo.

When Shisui attempted to use Kotoamatsukami in order to avert the Uchiha Clan Downfall, his right Mangekyō was stolen by Danzō Shimura, who felt Shisui's plan was futile and wished to protect the village in his own manner. Fearful that Danzō would take his other eye too, Shisui entrusted it to his best friend, Itachi Uchiha, and begged him to use it to save Konoha. Danzō transplants the eye he took into himself and uses it over the years to manipulate others to his way of thinking, using the power of Hashirama Senju to reduce its recharge time. Danzō destroys the eye before his death so that nobody else could have it. Itachi transplanted the eye he was given into a crow that he planned to use to re-ally his brother, Sasuke, with Konoha. He unintentionally used it on himself instead when he is reincarnated in order to break free of Kabuto Yakushi's control. Itachi incinerates the crow afterwards so that nobody else could have the eye.

Indra Ōtsutsuki
In the manga, Indra Ōtsutsuki was the first user of Mangekyō Sharingan. The individual abilities of each of his eyes were unknown, except that he was able to use Susanoo.

Shin Uchiha
 This Mangekyō Sharingan form is uniquely shared between multiple (yet connected) individuals. With his right eye, Shin Uchiha is able to telekinetically manipulate any objects after first branding them with a special mark. Shin's clones, being genetically identical to him, possess the same Mangekyō Sharingan design and with it the same telekinetic powers. A creature also shares the same Mangekyō Sharingan design with Shin.

Fugaku Uchiha
In the anime, Fugaku Uchiha had awakened his Mangekyō Sharingan after witnessing a sacrifice of his dear friend during the Third Shinobi World War. Although, not much is known about his Mangekyō, Fugaku was confident it was strong enough to control the Nine-Tails.

Hagoromo Ōtsutsuki
In the anime, Hagoromo Ōtsutsuki awakened this power after risking his brother Hamura's life to save him from Kaguya's control; however, the design of his Mangekyō Sharingan is unknown because his eyes evolved into the Rinnegan at the same time. While the individual techniques his eyes had are unknown, he was able to perform a massive Complete Body — Susanoo, which was roughly the size of the Ten-Tails.

Trivia

 * Originally in the anime, Itachi Uchiha was shown using techniques exclusive to the Mangekyō Sharingan without having it active. This is because Kishimoto had not revealed the appearance of the Mangekyō Sharingan in the manga yet. A true form of the Mangekyō Sharingan was first seen, from Itachi, while Sasuke remembered the events leading to the Uchiha Clan Downfall as he fought with Naruto Uzumaki at the Valley of the End.
 * Despite using his Mangekyō extensively for over a decade, Obito never displayed any signs of fatigue or deteriorating eyesight.
 * The manners in which an individual gains the Mangekyō Sharingan are almost parallel to how an Uchiha awakens their regular Sharingan for the first time, since both need intense emotions to awaken them.
 * In the manga, Sasuke Uchiha's Mangekyō Sharingan is the only one with an inverted colour scheme, boasting a red design and black iris.
 * In the novel, it is shown if a person is struggling between whether or not to feel saddened by a person's death, they will experience eye irritation, which will either fade if they end up not caring about said person or awakening the Mangekyō Sharingan if they end up feeling genuine sadness.