As all the lights are apparently willed out by the two accomplices, the Great Chain of Being is broken, and evil turns the world upside down. The light and goodness is taken away from Scotland as Duncan is killed.
Act Two opens in the darkness. In II, I, 6-7, Banquo said, "There is husbandry in heaven/ Their candles are all out." This the kind of night Macbeth wished for, where his deed may be hidden from everyone, including himself. MacDuff has come to wake Duncan, but instead finds him dead. It would appear to the faithful Scottish nobles that without Duncan, there is no longer any light. However, in an ironic twist, Macbeth is named king, thereby reversing the light and dark roles. But they are soon returned as Macbeth proves to be a bad ruler, however good of a soldier he was before. Different strange events have started to occur, like an eclipse, which shows how the darkness of Macbeth's actions envelops the earth. In act three, the darkness hides more murders when Banquo is killed on the way to the banquet and Fleance only nearly escapes. It is ironic that in III, III, 20, the murderers ask for, "A light, a light!" They are working under darkness and doing something evil, and perhaps it was Shakespeare's way of suggesting that the murderers did not really want to kill Banquo and Fleance. When the murderers report to Macbeth later in III, III, 18, they tell him about Banquo's murder and Fleance's escape; it was shown that more murders were again hidden in the darkness, for, "Who did strike out the light," points out that the light (goodness) was again gone from such dark dealings.
Act four is the climax of the dark imagery in the beginning with the witches brewing some more heinous concoctions. In IV, I, 25-27, the witches ask for something, "Slivered in the moon's eclipse," and for, "Root of hemlock digged i" th" dark." These would both be evil ingredients that would make the potion more dangerous.