Macduff is important to the plot because he is the one who eventually kills Macbeth. His family is important because Macbeth sent the murderers that killed Macduff's family. This was one of Macduff's motivations to fight Macbeth. Macbeth believed Macduff suspected Macbeth had killed Duncan. By this time, Macbeth was getting very paranoid. With hired murderers, Macbeth killed Banquo and tried to kill Banquo's son Fleance. Macbeth did not stop there. He sent the assassins to the Macduff house, where they killed his family. When Macduff finds out, he is overcome with grief. He tells Malcolm, who tells him that he needs to be a man. MACDUFF … All my pretty ones? Did you say all? O hell-kite! All? What, all my pretty chickens and their dam At one fell swoop? MALCOLM Dispute it like a man. MACDUFF I shall do so; But I must also feel it as a man: I cannot but remember such things were, That were most precious to me (Act 4, Scene 3). Basically, Malcolm is telling Macduff that inst...