# Macduff a character in the play Macbeth by William Shakespeare. Macbeth is accosted by three mysterious witches and hailed as the future king of Scotland. At the urging of his wife he murders the king (Duncan) and is then proclaimed king himself Macduff, Macbeth's former friend, turns against him after the murder and joins Duncan's son in raising an army to unseat him. In the last scene of the play Macduff challenges Macbeth to fight; one part of Macbeth's response is "Lay on Macduff." This is a well-known and often quoted line from the play.