In the play of Macbeth, Shakespeare introduces the main character, through the eyes of the one who knows him best, his wife. Lady Macbeth displays to the audience all of Macbeth's weaknesses; her ambition to have power becomes her husband's and this will bring out Macbeth's ambition to be king. She also proves that the strong may become the weak and the weak may become the strong. Lady Macbeth is a main character in this play because she introduces Macbeth and helps the reader to understand his character. At the start of the play she seems to be the more ruthless of the two. When the reader is first introduced to Lady Macbeth she is already planning the death of King Duncan. In order for her to have the courage to do the deed and ask that all woman emotions be removed from her, "Come, you spirits That tend on mortal thoughts, unsex me here, And fill me, from the crown to the toe, top-full Of direst cruelty! (p 257)" She is a key factor in this play because she links the male soul to the female body, showing that ambition can lead to violence.
When Lady Macbeth reads the letter from her husband telling her the news about becoming the Thane of Cawdor, Thane of Glamis and of the three witches that told him he would be king, she was overwhelmed by ambition to have power. She then goes on to plot the death of the King, then realizing that Macbeth would not go through with the plan unless she pushes him to do it, "Yet do I fear thy nature; it is too full o" th" milk of human kindness to catch the nearest way. Thou wouldst be great, Art not without ambition, but without the illness should attend it. (p 256)" She knows that Macbeth is a loyal warrior and it would be difficult, and she does it by questioning his manhood, "But screw your courage to the sticking-place And we"ll not fail. (p 260)" When the King arrives she makes Macbeth stay out of the room because his face releases the secrets that lye within, "Your face, my Thane, is as a book where men May read strange matters.