Here is something people simply don't understand. Some people say "Its in the manga so if you disagree, then you disagree with kishi" and others say "Oh that character said it but they don't know what they are talking about". For crying out loud people, you have to pay attention to the context. So far, gaara, sasuke, orochimaru, itachi, and the third raikage have boasted techniques that are "the ultimate defense". Obviously not all of them are right. When kabuto says that the edo tensei is the "strongest most unbeatable jutsu in the ninja world", he is hyping his OWN technique. This situation is different. Let me ask you something, why do you think that kishi even made zetsu watch that fight and commentate? Because he is a source of information for during the fight. Its like a sports commentator giving you unbiased facts during a game. His sole purpose in the plot was to say that the yata mirror is invincible and that kirin is literally fast as lightning. I'm not the biggest itachi fan, and i'm not fond of sasuke, but these are actual "manga facts". There sole purpose for being in the manga was to inform the readers that this actually IS the ultimate defense. Now i'm not saying that theres no way to speed blitz itachi in this form or anything, but i do believe that NO traditional attack (no matter how intense the magnitude of the force) will penetrate the yata mirror. If you agree/disagree, please inbox me or leave a comment