Those weird rituals that Hidan does are leading me to believe that he can take an enormous amount of pain, blood-loss, or just general physical damage. I also see the two chunnin exam leaders dying in a failed assassination. Asuma will most likely die in aiding shikamaru's escape, which will prolly end up leading akatsuki to konoha. Where naruto will encounter the akatsuki and finish the rasengan. BOOM Whirlwind rasengan kamehameha!!