At the beginning of the play, we see that the civil war raging in Scotland has brought out the best in Macbeth. He behaves nobly, exactly as one of Duncan's thanes should, slaughering the rebel Macdonwald and many of his men in combat. While this may alert modern audiences to Macbeth's capacity for extreme violence, Duncan is profoundly moved by his kinsman's contributions to the cause, exclaiming "O valiant cousin! Worthy kinsman!" So Macbeth certainly flourishes in the military aspect of the conflict. Yet in the wake of the battle, as Duncan names Malcolm his heir even as Macbeth hears from the witches that he will be king, a new conflict emerges, this time an inner conflict in which Macbeth wrestles with his conscience, fate, and his ambition to become king. Clearly this conflict brings out the worst in him, as he murders Duncan and claims the throne himself, thus setting in motion a series of murders that will eventually lead to his destruction at the hands of Macduff.