Like his father, Malcolm represents stability and lawfulness. But where Duncan stands as an old guard representation of what has come before, Malcolm’s prospects speak to the future. Literalizing the family dynamic, Malcolm doesn't merely offer a possibility of future peace; he would extend Duncan’s reign directly. However, Malcolm’s character also showcases the dangers and burdens of holding such a title. When Duncan is killed, Malcolm’s very life presents a challenge to Macbeth’s reign, and he must leave Scotland for fear of being killed.
In Act IV, Malcolm and Macduff discuss leadership. Even as Malcolm initially “admits” his own shortcomings and vices to gauge Macduff’s loyalty, the pair hold common ground in regards to their loyalty and love of Scotland, a crucial thread that speaks to the purely idealistic, if naive, trap of ruling. A tyrant like Macbeth seeks power for power’s sake, and therefore lacks the loyalty of those who put the nation first, like Duncan and Edward, and Malcolm and Macduff.
The younger generation’s hope for a more idealistic and enlightened society pits the viewpoints of Malcolm against those of Macbeth, whose persistent ambitions, expertise on the battlefield, and warring neuroses make him a turbulent, violent force within the play. Malcolm is driven to destroy Macbeth, recruiting Macduff to join him after his family too is killed. Here, Malcolm decides to do what is necessary and stop the usurper. Yet Malcolm still holds onto his humanity, furthering his contrast to Macbeth, who remains a cautionary figure for Malcolm. Macduff encourages Malcolm not to lose sight over what has been lost, as grief, not merely revenge, will keep him grounded when nearly everyone around him falls further into the temptation of power.
Even though it is Macduff who ultimately kills Macbeth, the play ends with Malcolm being sworn in as king, allowing Shakespeare to explore a contrast between the proper inheritance of one’s title versus the act of stealing it. Malcolm’s duty and responsibility prompt him to do what is right for the good of the nation, contrasting with Macbeth’s bloodthirsty attempt to thwart the natural order. Malcolm is the king by divine rule; Macbeth is a usurper. By the end, the former is rewarded, while the latter meets his demise, thus reinforcing the legitimacy of the line of succession. In his speech boasting of peace and just rulership, the coronation of Malcolm offers a chance for stability, much like what King Duncan stood for. Malcolm invites everyone to his ceremony, suggesting a new cycle of equality and order and marking a distinct contrast from the conflict that previously plagued the country.