Daughter of Pluto, born in 1928, with the unique ability to unearth precious metals and jewels, who grapples with a feeling of guilt and is perceived as an outcast at Camp Jupiter.

Son of Mars, initially unsure of his demigod abilities, embarks on a quest that leads him to discover the truth about his family's heroic legacy.

Half-brother to Hazel and son of Pluto, he plays a crucial behind-the-scenes role by providing valuable information for the demigods' quest.

Daughter of Bellona and a praetor at Camp Jupiter, she relies on her strong leadership skills and sharp judgment to manage camp dynamics amidst the uncertainty brought by new arrivals.

The Roman goddess of marriage and childbirth who orchestrates scenarios to prepare demigods like Percy for an impending war, despite her controversial methods.

The Roman god of war and father to Frank Zhang, he challenges his son to grow into his powers through quests central to the demigods' mission.

Percy's half-brother, a cyclops characterized by his kind heart and persistence, whose presence serves as a reminder of Percy’s past and familial connections.

The ancient earth goddess and antagonist, whose manipulative whispers and actions challenge Percy and Hazel throughout their journey.