Why should it damage Gai? Gai is not important anymore he basically disappeared in that battlefield and look where the bijudama explodes........probably a couple hundred meters above ground.Well did it damage Gai?.....I thought fvcking not! That fodder jutsu only does a simple lumberjack's job quicker, nothing more. Sasuke's PS can fly, enton rain GG. While on the other hand nuggets(iq of a testicle) has to try an figure out Sasuke's Jutsu, and we both know that's not happening....So in the end Sasuke still blitzes his abused ass.