Board Thread:Versus Debates/@comment-142748-20150410212019/@comment-3965545-20150411235422

He was very sick the entire fight, Black Zetsu even said he was overall slower and his reflexes were slower compared to his normal self, then said Itachi should be much better, much stronger. It got fatal around the time he used Susanoo, his organs were failing hence the blood coughing, holding his heart like he had a heart attack and subsequently dying. He was also just about blind when Kirin was used.

"Its can depend on air conditions, but the typical lightning bolt moves at 224,000 mph -- or about 3,700 miles per second. However, the light you see from the lightning obviously travels at the speed of light, which is roughly 670 million mph, or 186,000 miles per second." Itachi had Susanoo up and read for even THAT. Kirin is natural lightning. Itachi needs more than just reaction speed, that takes speed to be able to block that. Lightning is faster than the speed of sound, it is the speed of light according to Fulminologists.