I agree with that. Grace is a real jerk! In the first game she's kind of a jerk, but you only see her talking with Gabriel, and the way Gabriel acts in that game I can understand why Grace is a jerk to him. But in GK2, she's just flat out nasty, and not just to Gabriel.
And Minya's not entirely correct. Grace does later realize she's a jerk about one thing, but her personality doesn't change. Even later in the game she goes right back to being a bitch. Personally, I prefer the parts of this game where you play as Gabriel.
For some reason, Gabriel can get killed in this game but Grace can't (at least not as far as I know).