The Sea of Monsters characters

Also known as Perseus Jackson

Appears from the start

A thirteen-year-old demigod son of Poseidon, finishing seventh grade at a new school after the events of the previous summer. Loyal, quick-tempered, and brave, he is troubled by disturbing dreams of his friend Grover in danger and by news that the magical borders protecting his summer home for demigods are failing.

Appears from the start

A demigod daughter of Athena and Percy's closest ally, clever, proud, and a skilled strategist and fighter. She arrives to help Percy when monsters attack his school and joins his effort to save their camp. She carries old, complicated feelings about Luke, whom she once trusted, and a hard-won practicality about surviving as a half-blood.

Appears from the start

A satyr and Percy's devoted friend, who has gone off searching for the lost wild god Pan. Percy dreams of him in serious trouble: captured by a Cyclops on a distant island and forced to stall for time. Through an empathy link, Grover can send Percy fragments of his plight, drawing his friends toward a rescue.

First appears in chapter 4

A demigod daughter of Zeus, known from earlier events. Years ago, dying while protecting younger half-bloods at the camp's border, she was transformed by her father into a pine tree whose power shields the camp. In this book that tree has been poisoned, and its slow death is what leaves the camp's protective borders failing.

First appears in chapter 4

The immortal centaur who trains young heroes and directs the demigod camp. Because he is a son of the Titan Kronos, he falls under suspicion when the border tree is poisoned and is dismissed from the camp, forced to leave the demigods without their trusted mentor at a dangerous time.

First appears in chapter 4

A spirit summoned from the Underworld to serve as the camp's new activities director in Chiron's place. Cursed in ancient times so that food and drink forever escape his reach, he is petty and self-absorbed, favors cruel campers, and cares little for the demigods' safety.

First appears in chapter 5

A large, gentle, childlike boy who has befriended Percy at school and is treated as an outcast. He is revealed to be a young Cyclops, and Poseidon claims him as his son, making Tyson a half-brother to Percy. Immensely strong and skilled with his hands, he is eager to help and hurt by Percy's initial embarrassment over their kinship.

First appears in chapter 7

The god of travelers and messengers, and the father of Luke. He appears to Percy privately and gives him useful items for the journey ahead, including a thermos that holds the winds and multivitamins with strange effects. Pained by his son's turn to the enemy, he asks Percy to watch for Luke and not to give up on him.

First appears in chapter 7

A tough, aggressive demigod daughter of Ares who has clashed with Percy since his arrival at camp. She is chosen to lead the official quest to recover the item that can save the camp, and she takes the responsibility with fierce pride, determined to prove herself and resentful of Percy following on his own.

First appears in chapter 11

A demigod son of Hermes and former camp counselor who betrayed the gods to serve the reviving Titan lord Kronos. He now commands a monster-crewed ship and works to bring his master back to full strength. Bitter toward the gods, he is charming and dangerous, and still a wound to Annabeth, who once looked up to him.

First appears in chapter 11

The ancient Titan lord, defeated and cast down long ago, now slowly re-forming from scattered remains inside a golden sarcophagus aboard Luke's ship. He speaks into the dreams of demigods to tempt and torment them, and his growing power is the true threat behind the attacks on the camp.

First appears in chapter 16

A monstrous one-eyed Cyclops who lives on an island within the Sea of Monsters, tending mutant sheep and guarding the golden treasure the questers seek. He has captured Grover and, deceived by a disguise, believes the satyr to be a bride. Enormous and violent, he stands between the heroes and the object that can heal the camp.