Izanagi allows the person to do two things, making anything disadvantageous the cast suffers from an illusion such as injury/death, while at the same time keeping anything advantageous to the caster, such as the casters attacks part of reality. It is the ultimate Genjutsu cast on oneself, since it gives the caster full control over their own reality for a certain amount of time.
If Izanami is the opposite of Izanagi, than it would be the ultimate genjutsu cast on someone else, which would givethe caster control over their personal reality. Which would allow the caster to make anything advantageous to the target, such as buffs likeKabuto's SM & regeneration, illusions, as well as removing anything advantageous to the target from reality, like their attacks being made mere illusions.
This would give Itachi a certain amount of time where he essentially reverts Kabuto back to his "base" form (thus preventing him from covering his eyes as effectively)and dispelhis regeneration, thus allowing the Uchiha brothers to capture Kabuto during this time frame and cast Tsukuyomi on him to end Edo Tensei.
Not only would this be a very powerful technique, but it would allow Itachi to accomplish his objective, which issomething a-lotof theories I see leaving out. Also while this Jutsu would be powerful, it would not be an auto-win button, because it would only work for a certain period of time and while it does prevent the opponents attack from being effective, itwould not dispel the target's innate abilities such as their speed/strength/intelligence/etc... I also believe that Izanami probably won't be as effective against summons or someone who has a Bijuu.
What I mean by this is that, the summons & Bijuu won't be effected by Izanamidueto thefact that they have their own personal reality, so if say Kabuto gets hit by Izanami and he summons Manda V2, it's attacks will stillbeeffectiveand this is how I expect Kabuto to hold off the Uchiha brothers for a little while despite being under the effects of Izanami, he'll use Manda V2 and maybe the Sage Snake to defend himself making it so Izanami isn'ta complete stomp. Like wise if Naruto was hit by Izanami Kurama's powers would stillbeeffectiveand viseversa.
The final point I want to address is that if you think about it Izanami & Izanagi would than make a perfect pair, since with both Jutsu the person would gain complete control over reality considering both jutsu combined would allow the caster to control the enemies reality as well as their own, which would createanultimatecombo, I.E. Final Villain "level" power.
If Izanami is the opposite of Izanagi, than it would be the ultimate genjutsu cast on someone else, which would givethe caster control over their personal reality. Which would allow the caster to make anything advantageous to the target, such as buffs likeKabuto's SM & regeneration, illusions, as well as removing anything advantageous to the target from reality, like their attacks being made mere illusions.
This would give Itachi a certain amount of time where he essentially reverts Kabuto back to his "base" form (thus preventing him from covering his eyes as effectively)and dispelhis regeneration, thus allowing the Uchiha brothers to capture Kabuto during this time frame and cast Tsukuyomi on him to end Edo Tensei.
Not only would this be a very powerful technique, but it would allow Itachi to accomplish his objective, which issomething a-lotof theories I see leaving out. Also while this Jutsu would be powerful, it would not be an auto-win button, because it would only work for a certain period of time and while it does prevent the opponents attack from being effective, itwould not dispel the target's innate abilities such as their speed/strength/intelligence/etc... I also believe that Izanami probably won't be as effective against summons or someone who has a Bijuu.
What I mean by this is that, the summons & Bijuu won't be effected by Izanamidueto thefact that they have their own personal reality, so if say Kabuto gets hit by Izanami and he summons Manda V2, it's attacks will stillbeeffectiveand this is how I expect Kabuto to hold off the Uchiha brothers for a little while despite being under the effects of Izanami, he'll use Manda V2 and maybe the Sage Snake to defend himself making it so Izanami isn'ta complete stomp. Like wise if Naruto was hit by Izanami Kurama's powers would stillbeeffectiveand viseversa.
The final point I want to address is that if you think about it Izanami & Izanagi would than make a perfect pair, since with both Jutsu the person would gain complete control over reality considering both jutsu combined would allow the caster to control the enemies reality as well as their own, which would createanultimatecombo, I.E. Final Villain "level" power.