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 দ্বারা trying to kill Leon which made him accidentally kill her when he tried calming her down and take the ছুরি away from her which led to them wrestling for the ছুরি and bam Maizono's dead (read the জাপানি কমিকস মাঙ্গা 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 দুশ্চরিত্রা to Souda which really pisses me off since I প্রণয় Souda (and Leon!!!).