William Shakespeare's "Macbeth" tells of the rise and fall of the titular character through his own bloody deeds. Macbeth murders his cousin to become the king, and that act sets him on a downward trajectory that has him committing even more heinous crimes. Though Macbeth is fighting with and killing many other characters in the play, the main conflict is an internal one, between Macbeth's ambition and his morality.
Man Versus Himself
When the play starts, Macbeth is described as a noble, brave, loyal and honorable man. A chance encounter with three witches, who tell Macbeth that he will one day be king, starts the wheels turning in his mind. His wife, Lady Macbeth, further encourages him by planting the idea of killing the king in his head and then taunting his manhood when he hesitates to commit the act. These external forces only serve to exacerbate the internal conflict that Macbeth feels. He fights his ambition, which drives him to consider committing evil deeds that go against his sense of what is right and wrong. He knows that killing Duncan is wrong, but in the end, his ambition wins out, and he does it anyway.