Izanami

Izanami is one of the ultimate dōjutsu of the Uchiha clan. It is a genjutsu which affects the target through physical sensations shared between them and the user. Like its counterpart, in exchange for the temporary ability that it grants the user, the Sharingan with which Izanami is cast is rendered blind and loses its light forever. According to Itachi, this technique and Izanagi form a pair, but unlike the latter, which is a technique capable of altering destiny, Izanami is instead one that "decides" it.

To begin the technique, after selecting any arbitrary moment, the caster uses their Sharingan to remember the physical sensations both of their body and that of their opponent's during that instant like a photograph (represented as: A). The user must then intentionally replicate the same sensation and in the same way, memorise that instant with their Sharingan (represented as: A'). Izanami overlaps and connects these two identical bodily sensations (A and A'), as well as the flow of time between them, creating an infinite loop of events that entraps the opponent's consciousness.

Whilst under the effects of the technique, the target stands motionlessly as the loop of events continually replays inside their mind. Each time a loop is repeated, any physical damage incurred is reset as it were before the start of the loop, although the remains of severed appendages do not disappear. Despite being able to become consciously aware of their situation and act differently, the victim is unable to significantly alter or escape from the inevitable progression of these events. However, because this technique was created to reprimand and save the users of Izanagi, the victim is able to escape the infinite loop if they can acknowledge the real results of their actions and in doing so, accept their fate. In the anime, it's shown that there is no other way to undo this technique even by someone who has complete control over their chakra.

Creation
According to Itachi, there was a point in time where members of the clan abused the abilities granted by Izanagi, instead simply casting the technique as a means of escaping the undesirable results of their actions. Whilst this resulted in little issue if only one person were using Izanagi, if there were two or more casters, they would begin to fight amongst each other over personally favourable outcomes. Thus, as dōjutsu users were unlikely to succumb to ocular genjutsu, Izanami was created as a method to reprimand such clansmen, as well as save them from their own arrogance. By imprisoning them within an unalterable loop of events, the victim was forced to accept the reality they had created if they ever wished to escape the illusion. However, because of the dangers involved in using a technique with a way out in a real battle, Izanami became classed as a kinjutsu.

Influence
Like the various techniques used with the Sharingan, this technique is named after a Shintō goddess. In this case, it is Izanami, who, together with her brother and husband Izanagi, created the islands and other deities of Japan.

One of the most famous stories about Izanami tells the tale of how Izanagi goes into Yomi, the Japanese underworld, to retrieve her 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.