Percy Jackson is the titular character of the novel. He is a 15-year-old demigod and son of Poseidon and a mortal woman, Sally. When the novel begins, he is set to turn 16 in one week and is supposed to carry out the Great Prophecy:“I’d been hearing about the “Great Prophecy” for years, but nobody would tell me the whole thing. All I know was that I was supposed to make a decision that would decide the fate of the world—but no pressure” (41).

Thinking he is the one to carry out the Prophecy, Percy accepts the mission and embarks on his journey to save Mount Olympus from the Titan army. In many ways, Percy’s journey closely mirrors that of the traditional hero’s journey, a central theme of the novel. He accepts his quest, gains knowledge and tools, and battles his enemy. However, when fighting Kronos, the author reveals that it is Luke who will ultimately overthrow Kronos, and in this way the author problematizes the traditional hero’s journey by allowing it to move in a different direction.

Throughout his journey, Percy contends with the idea of predestination versus free will, another central theme of the novel. He accepts what he perceives to be his fate but also challenges it.