How is evil explored in the Play Macbeth. A dark night and a dark place are both symbolic of diablerie in the play Macbeth. Authors use these symbols to describe an evil character or setting. William Shakespeare employs the imagery of darkness in Act 4 and Act 1 of his play Macbeth to describe the agents of disorder and evil, the witches, Macbeth, and Scotland are all described as dark because they represent the evil. The witches in the first scene of Act 4 and Act 1 are depicted as agents of evil because of the dark domain around them. The witches meet in a dark cave. The cave is an appropriate setting for the witches because caves tend to rep