sai for sure, he had to kill his "brother" after bonding with him to kill his emotions. much worse than being picked 2nd over your little sister.
excluding Sauske and Naruto of course
Cause she's not a good fighter? What have we seen her do? Restrain the kyuubi, that's it. She would of gotten sealed faster than the 7 swordsman or even Gaara's dad.
