big deal if he mastered them all, he only wielded one of them anyways. And Zabuza was the best at Silent Killing, no one came even close to him. and he was the only one out of all of them to even be able to use the Hidden Mist Jutsu.i thought zabuza was pretty bad ass until seeing the other swordsmen in action. If mangetsu can master all of the swords he would be the strongest and most balanced