Prophecy in a narrative often serves as a plot device that foreshadows future events, adds tension and mystery, and drives the actions of characters. It can also create a sense of destiny or inevitability in the story, influencing characters' decisions and shaping the overall direction of the plot. Additionally, prophecy can add depth to the world-building by introducing elements of mysticism and the supernatural. Overall, prophecy plays a significant role in shaping the narrative by guiding the characters and events towards a predetermined outcome.