jshy7979

Answer: There is nothing in the film that states or even particularly indicates that Bill is somehow behind the deaths of O-Ren's parents. The only explanation we get is that their death was ordered by Yakuza boss Matsumoto, who brought in the thugs that killed her father. There is a semi-popular fan-theory that the man in white (Pretty Riki) is actually a young Bill, but to my knowledge, this was never confirmed by Quentin Tarantino. (In fact, according to the Kill Bill wiki, Tarantino actually denied they were the same person, but I can't find the source for that.) So there's literally no reason for her to go after Bill. As far as she (and the audience) knows, he was uninvolved in their deaths.

TedStixon

Answer: Yes, it's confirmed it in a post-release interview.

Grumpy Scot

Answer: It has been speculated for years, including on this site, that the sword-wielding killer in the anime sequence was actually Bill, but with the recent release of Kill Bill: The Whole Bloody Affair, it's now clear that that particular character is someone entirely different. Nothing in the movie suggests that Bill had anything to do with O-Ren's parents dying.

jshy7979

Answer: Bill was behind the killing of O-Ren's parents, we think. It is never clarified.

XIII

Answer: Now that "Kill Bill: The Whole Bloody Affair" has been released, this question can be answered. (Super minor spoiler ahead) I also thought that this character could possibly have been Bill, as they are shown to hold their swords similarly when not using them, plus the hair and the jewelry. But Tarantino has added an additional scene, showing that that character is not Bill. He is referred to as Matsumoto's second in command, Pretty Riki, and is killed.

jshy7979