Macbeth is a Scottish general and the thane of Glamis who is led to wicked thoughts by the prophecies of the three witches, especially after their prophecy that he will be made thane of Cawdor comes true. Macbeth is a brave soldier and a powerful man, but he is not a virtuous one. He is easily tempted into murder to fulfill his ambitions to the throne, and once he commits his first crime and is crowned king of Scotland, he embarks on further atrocities with increasing ease. Ultimately, Macbeth proves himself better suited to the battlefield than to political intrigue, because he lacks the skills necessary to rule without being a tyrant. His response to every problem is violence and murder. Unlike Shakespeare's great villains, such as Iago in Othello and Richard III in Richard III, Macbeth is never comfortable in his role as a criminal. He is unable to bear the psychological consequences of his atrocities.
The brave, noble general whose children, according to the witches' prophecy, will inherit the Scottish throne. Like Macbeth, Banquo thinks ambitious thoughts, but he does not translate those thoughts into action. In a sense, Banquo's character stands as a rebuke to Macbeth, since he represents the path Macbeth chose not to take: a path in which ambition need not lead to betrayal and murder. Appropriately, then, it is Banquo's ghost "and not Duncan's "that haunts Macbeth. In addition to embodying Macbeth's guilt for killing Banquo, the ghost also reminds Macbeth that he did not emulate Banquo's reaction to the witches' prophecy.
Act 3 Scenes 1.
In the royal palace at Forrest, Banquo paces and thinks about the coronation of Macbeth and the prophecies of the weird sisters. The witches foretold that Macbeth would be king and that Banquo's line would eventually sit on the throne. If the first prophecy came true, Banquo thinks, feeling the stirring of ambition, why not the second? Macbeth enters, attired as king.