I would have to say Maizono, not because I hate her as a character, but because she was the one who started the killing game by trying to kill Leon which made him accidentally kill her when he tried calming her down and take the knife away from her which led to them wrestling for the knife and bam Maizono's dead (read the manga with the killers point of view and why they did it since Leon's actions were never really explained in the game and anime). Since she's the reason Leon was executed that is why I hate her. Also I don't really like Sonia either since she's a bitch to Souda which really pisses me off since I love Souda (and Leon!!!).
