A daughter of Athena, Annabeth is known for her wisdom and strategic mind. She has been at Camp Half-Blood for five years and dreams of becoming an architect. Annabeth uses her intellect to solve problems, contrasting with Percy's impulsive nature.

A satyr and keeper, Grover is responsible for protecting demigods and escorting them to Camp Half-Blood. He is sensitive and cares deeply for nature. Grover aims to earn his searcher's license to find Pan, the god of wild places.

A demigod son of Hermes, Luke is older than Percy and Annabeth and leads cabin 11 at Camp Half-Blood. He struggles with feelings of abandonment and resentment towards the gods and plays a significant role in the events at camp.

Chiron, in disguise as Mr. Brunner, is a centaur and Percy’s mentor. He helps guide Percy at Camp Half-Blood, teaching him about Greek mythology and his demigod heritage.

The god of war who appears as a biker. Ares has a confrontational nature and becomes involved in the plot surrounding the stolen lightning bolt.

Percy’s loving mother who is his main motivation in the story. She provides comfort and support but becomes a focus of Percy’s quest efforts when he believes she is in danger.

Percy's father and the god of the sea. His absence and past actions create internal conflicts for Percy throughout the book.

A titan and the father of the gods, who manipulates events behind the scenes. Kronos’s influence serves as a lingering threat throughout the book.