Samehada and durability
a chakra eating living sword can feed Kisame chakra to replenish his own and even heal from it. I would think it is possible for him to break genjutsu thanks to Samehada. Kisame natural durability is great as well surviving days in samehada, alive before healing after his torso was blown open by Bee's lariate and breaking out of Yamato's wood binding jutsu after taking Hirudora. Kisame states to Bee That he doesn't tire and never falls with his durability chakra and Samehada it's not hard to believe. http://126.96.36.199/manga/mangas/Nar...ruto471_15.jpg
his natural chakra absorbing and healing
Kisame doesn't need Samehada to absorb jutsu or chakra. He was shown to absorb some guy's chakra and heal and Bee's lightning that was uses to stab Kisame in the arm and instead of the lightning infused sword going through Kisame the Lightning was absorb.....does this mean he can absorb chidori? Or even rasengan,fire or any elemental chakra that pierces his skin? Just look at it he can absorb elemental jutsu's once it pierces his his skin he basicly can not be killed by element jutsu's, that's OP. Now I see why Guy was the perfect counter to Kisame since he doesn't use ninjutsu.http://188.8.131.52/manga/mangas/Na...0Kisame/14.png
you can see it better in the anime.
Kisame can fuse with Samehada to become a shark like monster capable of sensing, extremly fast swimming breathing underwater and absorbing chakra just by touching. Since he can sense chakra in this state shouldn't he be immune to genjutsu? manga states in this form he has no weakness.http://184.108.40.206/manga/mangas/Nar...ruto471_17.jpg