So reanimated Itachi used Izanami on Kabuto. He then uses Tsukuyomi later. How is this possible?
I'll have to clarify a few things before I answer this question so it is completely answered.
- First off, he used Kotoamatsukami via Shisui's eyes to stop the Edo Tensei influence Kabuto had on him, but Shisui's eyes were placed in a crow.
- Secondly, Izanagi and Izanami can be used once in each eye, as shown with Madara.
The Izanami is an ocular genjutsu of the Sharingan, that is designed to trap an opponent without eyesight. It was developed to save and reprimand an Izanagi user, for they couldn't handle their power and eventually abused it during battles.
Both Izanagi and Izanami result in the loss of vision in one eye, until used by the other. Madara used Izanagi in one eye to come back to life after defeated by Hashirama Senju. This resulted in the loss of one eye, but his vision was then restored when he awakened the Rinnegan after implanting Hashirama's cells into himself with the intent of getting Wood Style.
As shown, only one eye turned white and the other Sharingan remained.
Itachi used Kotoamatsukami to stop Kabuto's influence on him with the Reanimation Jutsu, as it was set to activate once Naruto looked at Itachi's eyes, thinking that Sasuke would implant them. And Itachi had two Sharingan, meaning that Izanami would only blind him in one until he used it in the other eye as well. He then cast Tsukuyomi with the remaining eye, and thus could use it after using Izanami.