Most authors donate all the importance of the play to their main characters. The supporting characters do not seem more than extras. However, Shakespeare has given sufficient significance to all the supporting roles. A fact is that these roles help in shaping up the play. The first supporting character is Banquet is like a brother to Macbeth. Both of them fight battles together and share a very strong bond as well. The problems between them start when the reality of Macbeth is revealed in front of Banquet. Macbeth’s dead conscience allows him to kill his friend and hold on the position of the king.
The other two supporting characters are related to the campaign plotted against Macbeth. Once Macbeth acquires the throne, he finds it hard to remain in a calm mental position and gradually his dirty acts gain clarity. Hence, a campaign is plotted against him. Macduff is a brave soldier who represented his country for a long time in various wars. His son Malcolm also assists him in fighting Macbeth. The last battle between Macbeth and Macduff is an epic part of the play. In some scenes, one feels that Macduff would be killed at the hands of Macbeth. However, in the end, good wins against bad.
The character of King Duncan is also supporting to some extent. He captures the scenes for a short time span before he is killed. He is a soft person who cares for everyone around him.