Izanagi

Izanagi is a genjutsu performed with the Sharingan.

Overview
With a normal genjutsu, a user will apply an illusion to a target's senses, causing the target to experience things that are not real. With Izanagi, the user applies an illusion to reality itself, giving the user control over what is and is not real for as long as Izanagi is active. Users typically do this in order to protect themselves, negating any injuries they receive or even their deaths. When this happens, their injured self fades away as an illusion and their non-injured self immediately materialises in the previous self's place. In the anime, users are shown extending Izanagi's influence beyond their personal reality, affecting their surroundings and those within it.

Izanagi is based on the Creation of All Things Technique, used by the Sage of Six Paths to turn imagination into reality. The process is explained to use spiritual energy – which forms the basis of Yin Release – to create shape from nothingness. Then, through the application of physical energy – which forms the basis of Yang Release – the shape has life breathed into it. Members of the Uchiha clan, as descendants of the Sage, perform Izanagi with their Sharingan. In exchange for the brief control over reality that Izanagi grants them, the Sharingan that they perform it with becomes blind; only awakening the Rinnegan restores the eye's vision. Because the Uchiha prized their Sharingan, to lose it in this way prompted them to label it kinjutsu.

Because Uchiha only possess half of the Sage's chakra, they can only keep Izanagi active for a few seconds. To maximise Izanagi's duration, it is necessary to recreate the Sage's chakra by also having genetic material of the Sage's other descendants, the Senju. Danzō Shimura receives both Uchiha and Senju implants, allowing him to use Izanagi for one minute. As this is still not very long, he has ten Sharingan implanted in his right arm, giving him up to ten minutes' worth of Izanagi with breaks in between as he chooses. Since he is not an Uchiha, each use of Izanagi causes Danzō's chakra to drop significantly. Obito Uchiha, because he has control over the Senju cells he uses, is able to keep a single Izanagi active for significantly longer than Danzō.

As with other Sharingan-based techniques, Izanagi can be programmed to activate under certain conditions. Madara Uchiha did so to undo his death after he'd been entombed, restoring him to life unbeknownst to anyone.

Influence
Like the various techniques used with the Sharingan, this technique is named after a Shintō god. In this case, it is Izanagi, who, together with his sister and wife Izanami, created the islands and other deities of Japan.

One of the most famous stories about Izanagi tells the tale of how he goes into Yomi, the Japanese underworld, to retrieve Izanami after she died giving birth to the Shintō fire god, Kagutsuchi. In Yomi, he manages to get Izanami and they both try to leave, however, Izanagi was not supposed to look at her before they escape. Right before they reach the exit, Izanagi looks back and sees her in a decayed form. Frightened, Izanagi flees from Yomi and blocks the cave. Izanami curses Izanagi saying that she will kill 1000 people per day. In response, Izanagi says that 1500 people will be born each day. In another variation of the story, it is stated that Izanami told Izanagi to leave, however, he came back while she slept and lit a fire that revealed her decayed form, prompting him to escape out of fright, and barricade her inside with a giant boulder.

After his failed attempt to get Izanami, he washed himself in a stream. As he cleaned his left eye, Amaterasu was born, as he cleaned his right eye, Tsukuyomi was born, and as he cleaned his nose, Susanoo was born.

Trivia

 * Because members of the Uchiha clan previously abused the use of Izanagi, Izanami was created as a way to punish those who would misuse it. Like Izanagi, Izanami also blinds the Sharingan that it is performed with.
 * During initial depictions of Izanagi, the blindness it causes is represented by the eye's lids closing. After the blindness caused by Izanami is depicted as turning the eye a blank white, Izanagi starts being depicted the same way.
 * In the Naruto Shippūden: Ultimate Ninja Storm series, Danzō uses this as part of his ultimate technique, letting his Wood Release go out of control, creating a tree that crushes both himself and the opponent, and activating Izanagi at the last moment to escape unharmed.
 * Despite Madara using a time-activated Izanagi in the manga, he is not listed as a user of Izanagi in Jin no Sho.