Board Thread:Versus Debates/@comment-31338621-20200309130706/@comment-32685487-20200311190949

Itachi knows about Kamui, he just doesn't know the exact specifics of it. He knows Obito can warp back and forth. Obito was saying that if Itachi knew the workings of his intangility, then Obito himself would be dead. He isn't doubting in the slightest that Itachi could kill him, and he made it clear Itachi could of killed Sasuke.