nice thread, it wout be close but i think kakazu would win mostly because kisame would not be able to kill him 5 times probably 3 max, and the fact that kakazu is like over a hundred years old
For one, it doesn't turn the body into diamond, it just makes it as hard as diamond. If that was the reason then Kakuzu would take on all of the properties of diamond, including its shine.
2nd: Another misconception is the whole "diamond is brittle". Diamond cracks under sharp exertion of force not because it is hard, rather it does because it is brittle. Along with hardness, brittleness is another property of diamond. In engineering, hardness was never, is never, and will never be the same as brittleness. So Yes, diamond is brittle, but also hard, and the databook didn't say "Domu is as brittle as diamond". No where in canon was Domu associated with any other property of diamond besides its hardness. If Kakuzu were simply a giant diamond, Chouji Spiked Human Bullet Tank would have cracked him. That attack cratered the ground."
"diamond is hard,not strong,you know you can take a hammer and crush a diamond right?,diamond is harder than steel,but steel is way stornger,so kimi's bones being said to be above steel while in base(not even counting CS) means it is indeed above doton domu in strength,not hardness. Also it clearly says gaara crushes the HARDEST minerals,not STRONGEST. Kimi's bones resisted samurai chakra blades in base IIRC,but the pressure exertet by a 13 yr old gaara forced him to go CS1 first,then CS2 for the desert requiem. Kimi's bones in base would easily pierce a tree,or rock."