It is a very interesting aspect of this play that before we even meet Macbeth in person we are given a presentation of his character by others. In this case, Duncan, the King of Scotland, waiting to hear for news of how the battle is going, is given an account of Macbeth's valour, bravery and pugnacious spirit that, if we believe the account of the Captain in this scene, turned the tide of the battle in Duncan's favour. Note what the Captain says:
For brave Macbeth (well he deserves that name),
Disdaining Fortune, with his brandish'd steel,
Which smok'd with bloody execution,
Like Valour's minion, carv'd out his passage,
Till he fac'd the slave;
Which ne'er shook hands, nor bade farwell to him,
Till he unseam'd him from the nave to th'chops,
And fix'd his head upon our battlements.
Aspects to focus on in this description include Macbeth's valour, but also the bloody nature of the punishments he exacts upon the treacherous Macdonwald. The gruesome and graphic nature of what he does to his enemy seems to foreshadow his capacity to commit other gruesome and graphic acts, such as the murder of Duncan and the slaughter of Macduff's family. Macbeth is elsewhere described as "Belladonna's bridegroom," refering to the Roman goddess of war. We thus are given the impression of a brave but ruthless, bloody individual who is skilled in war and battle and has the confidence of his king.