It would be pretty cool if Kisame actully betray itachi and they get in* huge fight itachi would win like i said before with tsukoyomi(mangekyo sharingan)
Wouldn't be as easy as u think.* Even though Kisame kinda gets ordered around by Itachi he is definitely in the top three in the Akatsuki.* He has waaaay more chakra than Itachi, and the mangekyo doesn't do much against dodging his water*attacks*if he's using it in genjutsu.* Besides, who do u think Itachi copied the water techniques from anyway.* Being that he is a shark-like being you better believe he can perform jutsu very few hidden mist ninja could...
true,but kisame i think only has 1 jutsu which is water shark bomb jutsu and kisame has that big sword but the leaf village is the strongest village and the uchiha clan is the strongest clan in the leaf village and that makes itachi and sasuke and maybe tobi the strongest but kisame is the 2nd strongest in* the akatsuki.