Riordan depicts growing, awakening, and re-awakening powers to foreshadow the battles to come and to symbolize personal development. On the Olympian side, demigods like Percy and Nico develop abilities that are specific to their godly parents. Neither demigod can initially control his strength. Through trial and error, they learn to manage their powers, which still cause physical discomfort to the half-bloods and are barely enough to contain the Titan army. Riordan suggests that a huge expansion of power will be necessary for the imminent war.

The stages of development for divine abilities align with the stages of the demigods’ personal development. At the Triple G Ranch, Percy decides to be a different kind of hero than Hercules, which is the moment his powers awaken. By the end of the book, when Percy has matured, he can control the output of his powers to save Juniper, though his lingering pain denotes that he still has room to grow. Nico’s growing strength aligns with his growing anger and thirst for vengeance. As Nico works through his grief and forgives Percy, he controls his power more effectively: He faints after the battle of Camp Half-Blood, but this does not indicate another decline in his mental state.