Izanami is alot simpler than Izanagi, in the sense that Izanami is easier to understand.
Izanami is a punishment, originally used on those who abuse Izanagi, giving them a chance to change their ways without losing their eyes.
Izanami is an infinite loop. It is triggered by a specific action by the user, and over several turns, all actions that happen during this loop will repeat, and the technique finishes with an identical move from the user. Once trapped, the opponent is stuck for eternity, going over the exact same set of events from the moment the loop started till it ended. This technique is supposed to set the opponent into reflection, let them think of their actions, and how they have done wrong. Once they truly give up, and realize their wrongs, the genjutsu is broken.
This is scary strong. Izanagi doesnt event stand a chance, as this was created to hard counter Izanagi. its also reletively easy to set up, as long as you have freform or strong passive techniques, like susanoo. Only known way to break this is to either force the user to not complete the loop, or to use Yin mode, but idk how Yin mode would stand up if it wasnt already activated once the Loop has started. If Yin mode was activated during the looping, and the loop was complete, idk if they could use Yin mode to break it as they are trapped into those series of actions.
Izanami is the ultimate eye jutsu of the sharingan, its the be all end all of an opponent. Even if they manage to come around, they are so exhausted they cant fight back. Also, so much time can pass in the real world, that more than likely, if the user decided, the opponent could be beheaded or killed long before they even realize they are in a loop.
The best way i see it of understanding i quite simple:
Izanagi - The ability to re write your fate and that around you
Izanami - Lock in fate. You have to accept the terms of your fate
It ties in with the uchiha backstory Itachi told of how Izanami was maid to counter those who abused izanagi. Those who abuse godly powers to avoid their fate had to accept no matter what, the outcome was set.
The exact way to set it up, is to create the initial loop in the first place. It would be like creating a gif where you want to look like it never ends. A guy running around in a circle. Although it's the same gif playing over again, because it's going around in a loop, it looks like it goes on forever repeating the same process.
The initial action being where he starts running, how he starts running, the direction, the conditions around him. The end of the loop is where he starts this action again, in the exact same position, pose, area, surrounding. That way the gif would seem like an infinite loop.
In the RP, Izanami is the same principle with the condition of a two turn set up. This is hard but at the same time, not impossible.
( Doujutsu: Izanami ) - Eye Technique: Izanami
Type: Offensive/Supplementary
Rank: Forbidden
Range: Short
Chakra Cost: 100
Damage: N/A ( loss of a Sharingan eye )
Description: Izanami is one of the ultimate techniques of the Uchiha clan, said to have been created to deal with Izanagi users that went mad or abused it. 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 sealed away and loses its light forever, leftblind for the rest of the match. According to Itachi, this technique and Izanagi form a pair, but while Izanagi 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 and every detail that surrounds him and his opponent as well as the information gathered by all his senses and that of their opponent's during that instant like a photograph. The user must then intentionally replicate the same sensation, feeling and moment and in the same way, memorise it with their Sharingan. Then, upon casting the technique, Izanami overlaps and connects these two identical "moments" 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. 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.
Note: Can only be used by Uchiha bios and the user must have mastered all Sharingan Genjutsu as well as gained access to MS or EMS, even if he doesn't need it to cast the illusion.
Note: Can only be used once per eye, after which the used eye loses its light for the rest of the fight.
Note: Doesn't require eye contact and takes 2 turns to set up and then trigger, during which the user can't use Genjutsu on the enemy.
Note: The user is left noticeably exhausted once the technique is fully triggered, while the target is left locked inside the illusion for up to 3 turns, unable to move or be aware of anything from the real world during that time. During those 3 turns, the user can make use of Genjutsu to interrogate the target freely without him knowing. After the 3 turns pass, the target is released but left in an exausted state, unable to fight or flee.
Note: Once triggered, target can't release himself from the illusion for the full 3 turns.
For example. The one time i used Izanami was a few years back against ned. I said i'd win in two moves. I had susanoo active, and i shot an arrow with susanoo at him, saying i memorised that situation. Two turns later, I shot another arrow at him, creating a loop. The condition being set was him on the ground, mid range infront of me, being shot by an arrow. I believe the first time he dodged, maybe blocked.
Now the real power is that Izanami sets ones fate, their destiny, that they can't avoid, they must accept.
"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."
"Note: Once triggered, target can't release himself from the illusion for the full 3 turns. "
You asked me about them breaking it with yin mode. But the jutsu itself say's they can't escape these events. You are setting their fate they must truly accept.
For my fight against ned it was that he would be hit by the arrow, that he would lose. He can't dodge or block it, because then the loop would never end, he had to accept his fate was to be hit by the arrow and that would be the end.
Your true power comes from you actually deciding their fate. Which they then must accept. If they have to accept no matter what they will be stuck in that loop until they realise they will never have the power to overcome it alone, that would be truly OP, but you can set it up to be that way. So if they were like "I'm going to counter with yin mode", they couldn't, the condition is to accept their fate of lack of power, to my understanding anyway. The jutsu says it can't be broke. And look how long kabuto spend trying. Izanagi itself, one jutsu made to alter ones own fate, can't bend reality to release this loop. Remember that.
Do you have any questions apart from what you asked me on discord