Macbeth's ambition for power leads to his tragic downfall. His ambition is first sparked by the witches' prophecies and is further fueled by his wife Lady Macbeth's ambitious nature. Driven by their mutual desire for the throne, Macbeth commits regicide by murdering King Duncan. However, as Macbeth becomes increasingly paranoid and tyrannical in his rule, he loses the trust of his men and commits further violent acts to hold onto his power. His unchecked ambition ultimately destroys him.