Because we first hear of Macbeth in the wounded captain’s account of his battlefield valor, our initial impression is of a brave and capable warrior. This perspective is complicated, however, once we see Macbeth interact with the three witches. We realize that his physical courage is joined by a consuming ambition and a tendency to self-doubt—the prediction that he will be king brings him joy, but it also creates inner turmoil. These three attributes—bravery, ambition, and self-doubt—struggle for mastery of Macbeth throughout the play. Shakespeare uses Macbeth to show the terrible effects that ambition and guilt can have on a man who lacks strength of character. We may classify Macbeth as irrevocably evil, but his weak character separates him from Shakespeare’s great villains—Iago in Othello, Richard III in Richard III, Edmund in King Lear—who are all strong enough to conquer guilt and self-doubt. Macbeth, great warrior though he is, is ill equipped for the psychic consequences of crime.
Before he kills Duncan, Macbeth is plagued by worry and almost aborts the crime. It takes Lady Macbeth’s steely sense of purpose to push him into the deed. After the murder, however, her powerful personality begins to disintegrate, leaving Macbeth increasingly alone. He fluctuates between fits of fevered action, in which he plots a series of murders to secure his throne, and moments of terrible guilt (as when Banquo’s ghost appears) and absolute pessimism (after his wife’s death, when he seems to succumb to despair). These fluctuations reflect the tragic tension within Macbeth: he is at once too ambitious to allow his conscience to stop him from murdering his way to the top and too conscientious to be happy with himself as a murderer.
As things fall apart for him at the end of the play, he seems almost relieved—with the English army at his gates, he can finally return to life as a warrior, and he displays a kind of reckless bravado as his enemies surround him and drag him down. In part, this stems from his fatal confidence in the witches’ prophecies, but it also seems to derive from the fact that he has returned to the arena where he has been most successful and where his internal turmoil need not affect him—namely, the battlefield. Unlike many of Shakespeare’s other tragic heroes, Macbeth never seems to contemplate suicide: “Why should I play the Roman fool,” he asks, “and die / On mine own sword?” (5.10.1–2). Instead, he goes down fighting, bringing the play full circle: it begins with Macbeth winning on the battlefield and ends with him dying in combat.