What is the role of the character 'MacDuff' in Macbeth?

MacBeth's rival for the throne. Macduff, the thane of Fife, is a Scottish nobleman. He travels with Duncan to Macbeth's castle, and with Lennox, arrives the morning after the king has been murdered to awaken Duncan, but instead finds him dead. Macduff announces to the gathered nobleman, including the king's sons, that Duncan has been killed.