Board Thread:Naruto Discussions/@comment-26538017-20150706222651/@comment-5407586-20150708134003

As powerful as Izanagi is, it has a very huge weakness. It has to be activated first. If Madara had activated Izanagi after being stabbed by Black Zetsu, it wouldn't have changed the situation he was in. Had he activated Izanagi before being stabbed, he could've escaped being possessed by Kaguya.

To clarify things: Izanagi changes only what happens in one's personal space in the interval of time between the jutsu's activation and the moment the Sharingan goes blind. Nothing else.