Final answer:
Malcolm fulfills the witches' prophecy in Shakespeare's Macbeth when he orders his soldiers to use branches from Birnam Wood as camouflage, making it appear as if the forest is moving towards Dunsinane, as prophesied.
Step-by-step explanation:
Malcolm unwittingly fulfills one of the witches' prophecies in Shakespeare's Macbeth. As the play progresses, Malcolm becomes a significant figure who challenges Macbeth's tyranny. In Act 5, Scene 7, Malcolm orders his soldiers to cut down branches from the trees of Birnam Wood and use them as camouflage while advancing towards Macbeth's stronghold at Dunsinane. This action inadvertently realizes the prophecy that Macbeth shall not be vanquished until 'Great Birnam Wood to high Dunsinane Hill shall come against him.' Malcolm's strategic ploy of using tree limbs for concealment gives the appearance of the forest moving, thus fulfilling the witches' prophecy and leading to Macbeth's downfall.