In Shakespeare's Macbeth, the principle character Macbeth is a representation that reinforces the idea of good and evil through use of conventions and techniques such as dialogue, dramatic exposition, foreshadowing, symbolism, asides and soliloquies. Macbeth is at first viewed as a protagonistic figure by the other characters and the audience. Shakespeare makes use of dramatic exposition to introduce Macbeth as a patriotic warrior. This is supported by Macbeth's dialogue and actions in the introductory scenes. For example, when awarded the title Thane of Cawdor by King Duncan, Macbeth conducts himself graciously through dialogue and appears humble to his colleagues and the superior king. However the audience, soon after the meeting of the witches, learns of the dark nature of Macbeth through his several soliloquies and asides. "Let not light see my black and deep desires" (act 1, scene 4). This aside shows us that Macbeth is aware of the evil in his emotions, but avoids accepting that people should know of his true intentions. .
Shakespeare uses multiple techniques like dialogue and symbolism effectively to create dramatic irony. The audience quickly learns that Macbeth's choice of actions has resulted, and continues to result, in destroying the values and honourable legacy he would like to be known for. However, Macbeth doesn't discover this realisation until it is far too late. This is evident in his dialogue with Seyton "And that which should accompany old age, as honour, love, obedience, troops of friends, I can not hope to have " (act 5, scene 3). As the plot unfolds it seems that the playwright's representation of Macbeth alters and gradually evolves until we are left with almost a completely new character at the end of the play. It is possible to identify certain points along the plot that are pivotal in the apparent change in characteristics of Macbeth. For example, in the first scene of act II an imaginary dagger points Macbeth toward Duncan's chamber.