List of characters

Main characters

 * Percy Jackson, son of Poseidon
 * Annabeth Chase, daughter of Athena
 * Grover Underwood, Percy's best friend
 * Thalia Grace, daughter of Zeus
 * Chiron, son of Kronos and Trainor of heroes
 * Nico di Angelo, son of Hades
 * Clarisse La Rue, daughter of Ares
 * Luke Castellan, son of Hermes
 * Tyson, son of Poseidon and Percy's half brother
 * Rachel Elizabeth Dare, immortal and,  currently and The Oracle of Delphi

Olympians

 * Zeus, god of the skies king of Olympus and Thalia's father
 * Hera, goddess of marriage in the queen of Olympus. She has no demigod children.
 * Poseidon, god of the seas and father of Percy and Tyson
 * Amphitrite, immortal wife of Poseidon and rather motherly with her stepson, Percy
 * Delphin, god of dolphins
 * Palaemon
 * Triton, Amphitrite's and Poseidon son and Percy's half-brother who he has a sibling rivalry with
 * Demeter, goddess of the harvest
 * Persephone, goddess of spring and the queen of the underworld
 * Ares, God of War and Clarisse's father
 * Deimos, God of fear
 * Phobos, God of terror
 * Athena, goddess of wisdom and the mother of Annabeth Chase
 * Apollo, god of the sun
 * Artemis, goddess of the hunt
 * Hunters
 * Hephaestus, the gods blacksmith
 * Aphrodite, goddess of love
 * Hermes, messenger of the gods and father of Luke castellan and the Stoll twins, Connor and Travis
 * Dionysus, god of wine
 * Hades, god of the underworld
 * Hestia

Hestia

Aeolus

Elpis

Ganymede

Hebe

Hecate

Hudson River

Iris

Janus

Kymopoleia

Morpheus

Melinoë

Nemesis

Terminus

Pan