Minato Namikaze, the Fourth Hokage.
Also, Hiruzen didn't stop the coffin. Minato's soul is sealed within the Death God, so he couldn't be revived with Edo Tensei.
you have to simply believe that this jutsu wasnt fully developed in part 1 we didnt know if a soul was sealed it couldnt be revived. but now in part 2 orochimaru can do w/e dafuq he wants to, cause as far as i knew he was sealed to all doom by itachi. also there was the possibility he could revive sealed souls cause he is fn orochimaru and planned to do it himself. "oh shiz sasuke, i didnt expect you to be the one to revive me."
oh yea kudos Kishi for making one of the most bad-ass villains i've seen in any manga ever. he just keeps coming back with new ways to break the rules.