Lady Macbeth- Lady Macbeth
Although Macbeth was the one who held the sword, it was Lady Macbeth that manipulated him into taking the lives of many. In fact, one of the most recognizable scenes in Macbeth is when she hallucinates blood on her hands from Macbeth's many murders caused by her mention. Although she gets her share at the end of the book/film, that doesn't change her effect on history, and it doesn't cleanse her of her sins.