Oh, of course Milady isn't a misunderstood lamb, she's quite responsible for her choices later, BUT in the episode with Athos specifically, I regard her as the one wronged. She didn't do anything to him but marry him without telling him about her past (and what kind of husband needs a fall from a horse to see his wife's shoulder for the first time anyway, I ask you?), and he, according to both of them, immediately responded by hanging her on the next tree. Not for her crime - he had no idea what she had done or hadn't, he just knew by the mark on her shoulder she had to be a criminal -, simply because his sense of honour was outraged by the idea of having married a criminal. This makes him a man of his time, but not necessarily a sympathetic one, and certainly not the victim in this marriage.

D'Artagnan: kills me in the last novel, when the others are either corrupt, gone or otherwise lost. I really feel for him there.