Itachi and Kisame
No Prep Time
Character Version Prime Itachi
Setting Hidden Mist Village
@SpeedForceSpider: Kisame's sword could absorb some of his energy. But i think Kenpachi has the edge in raw power.
Raw power and speed to be exact. That is why I said the only way they can win is through genjutsu assuming it can work. And does Reiatsu have the same energy properties as chakra in Naruto? It would for the Samahada to be able to absorb his energy.
Kisame will fall first. I can imagine him trying a mist technique to hide from Kenpachi but as seen against Tousen that just won't work.
However I believe in the end Itachi will win because he'll realise how powerful Kenpachi is after he disposed of Kisame so easily. He'll activate his Susanoo and Kenpachi being Kenpachi will be intrigued by this and want to test how powerful Susanoo is. Little does he know that the Sword of Totsuka will end him.
Well I guess it really depends on what kind of mood Kenpachi's in.
If he feels like testing Itachi's Susanoo then he will lose but if he's just bored and wants to end it then I don't really see how Susanoo will provide much defence against him. Although having said that we never really got to see how much defence the Yata Mirror provided but still I don't think it would be enough.
Itachi's Susanoo was strong enough to stop Kirin when he was on deaths door. Plus top tier Naruto characters are on a par with the captains in terms of speed, with the exception of FGT Ichigo and hollow Aizen. Strength and durability goes to Kenpachi in this fight, but versatility and intelligence is stacked in favour of the team, thus giving the team the win here I think.