The chorus in the time of the Greek play was used to define the mood of the crowd and would often reflect what they were thinking and in the process make sure to reflect what they should be thinking.
At this point in the play it is clear what has come of the man Creon so the chorus shifts in tone and identifies him as the villain as he is now to do acts that he will never find retribution for.
Thus, the chorus shifts its view on Creon from someone in control to someone who has commuted hubris.
