Macbeth

This depends on what point in the play you are referring to.

Lady Macbeth played quite the significant role in Macbeth. Not only was she the reason that Macbeth would strive for the throne that King Duncan had, but also trigger the significant changes of Macbeth's greed, ambition and thirst to kill. She begins by describing, after receiving a letter from her husband about the withces propechies of his becoming Thance of Cawdor and King of England, how she asks the gods to "unsex me here" because she believes her husband is incapable of being a King due to his cowardess and light-hearted, guilty nature. After her husband returns home, she begins to dehumanize him by calling him names and questioning his manhood. She, greedy for power and a name in England, tells her husband not to worry about the murder of Duncan because she would plan it out, he would merely need to murder Duncan himself and then plant the daggers back on the guards so they would be blamed for his death. Macbeth, once he has fulfilled the duty of murdering King Duncan, he becomes afraid that the citizens of England may find out, and question if "all of Neptune's oceans water cleanse this blood from my hands,?" along with other guilt-filled questions and mourning. Lady Macbeth, wearing the pants in the relationship, tells Macbeth that "my hands are of the same color, but I shame to wear a heart so white." Lady Macbeth plays a large role in influencing Macbeth to follow through with murder to maintain the crown and hide their deceit and murderous affairs. By the end of the play, she becomes insane by slepe walking and being unable to wash the blood from her hands, and leads to her suicide. She, besides the witches, was the other major player in leading to Macbeth's ambition, love for murder and eventually, his downfall.