The Sea of Monsters: Character List

Percy Jackson

The courageous and snarky thirteen-year-old son of Poseidon, and the protagonist of the series. Percy leads a quest into the Sea of Monsters to rescue his friend Grover from a Cyclops and save Camp Half-Blood in the process.

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Annabeth Chase

The clever and pragmatic thirteen-year-old daughter of Athena, and one of Percy’s best friends. Annabeth frequently relies on her superior intellect to save herself and her friends from danger. However, over the course of the novel, Annabeth learns that her greatest strength also has the power to become her greatest weakness.

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Tyson

A baby Cyclops (that is, a one-eyed giant), and Percy’s half-brother. Tyson’s appearance and stilted speech initially cause Percy to resent Tyson, but he soon sees the error of his ways and comes to love and value his new younger brother. Tyson is immune to fire and is a gifted metalworker.

Grover Underwood

A satyr (a half-human, half-goat), and one of Percy’s best friends. Grover is captured by the Cyclops Polyphemus and he creates an empathy link so that he can communicate with Percy through his dreams. Percy ventures into the Sea of Monsters to rescue Grover and steal the Golden Fleece, which is also in Polyphemus’s possession.

Clarisse La Rue

A combative and aggressive daughter of Ares. Clarisse is awarded the quest to search for the Golden Fleece and is initially angry that Percy and Annabeth are also looking for it. However, over the course of the novel, Clarisse learns to work together with her fellow demigods.

Chiron

A centaur (half-horse, half-man) who is the activities director at Camp Half-Blood. Chiron trains the campers and helps turn them into heroes. He is fired from his post after Thalia’s tree is poisoned, but he is rehired after Percy and his friends clear Chiron’s name.

Kronos

The king of the Titans who is slowly re-forming after being forced to spend an eternity in Tartarus, a prison in the deepest part of the Underworld. Kronos is recruiting an army of monsters and demigods and is plotting to overthrow Mount Olympus. He is highly interested in a prophecy that concerns the Age of the Gods.

Luke Castellan

A son of Hermes who resents his father and the other gods. He has joined forces with Kronos and is working with him to overthrow Mount Olympus. His betrayal hurts Annabeth, because she used to think of Luke as family.

Polyphemus

A Cyclops who is in the possession of the Golden Fleece. He weaponizes the Fleece’s powerful nature magic to lure satyrs to their death. At the start of the novel, Polyphemus captures Grover, but Grover buys himself some time by tricking Polyphemus into thinking that he is a lady Cyclops.

Agrius and Oreius

Brothers who are half-man, half bear, also known as the “Bear Twins.” The two monsters work for Luke and do his bidding. Percy and his friends first encounter the brothers when they are captured aboard the Princess Andromeda.

Ares

The Greek god of war and Clarisse’s father. Ares visits his daughter on her quest and cruelly tells her to not let Percy and Annabeth steal her glory.

Argus

A one hundred-eyed giant who works as the head of security for Camp Half-Blood. He is fired from his job when Chiron is blamed for poisoning Thalia’s tree.

Athena

The Greek goddess of wisdom, and Annabeth’s mother.

Charybdis

A sea monster with a giant mouth who swallows great amounts of water to create massive whirlpools. She, along with Scylla, guards the entrance to the Sea of Monsters.

Circe

A powerful sorceress who runs C.C.’s Spa and Resort. She separates Percy and Annabeth when they accidentally land on her island and turns Percy into a guinea pig—the fate she bestows upon all men who wash up on her island.

Dionysus/Mr. D

The apathetic and snarky god of wine who is acting as director of Camp Half-Blood as a punishment for offending Zeus.

Edward “Blackbeard” Teach

A pirate captain who, along with the rest of his crew, was turned into a guinea pig when they landed on Circe’s island. Blackbeard and his crew are returned to their true forms when Annabeth saves Percy and the two then steal Blackbeard’s ship, the Queen Anne’s Revenge.

George and Martha

The talking snakes on Hermes’s staff.

The Gray Sisters

Three old women (Anger, Tempest, and Wasp) who share a single eye and a single tooth. The sisters can predict the future and operate a taxi service which Annabeth hails to take her, Percy, and Tyson to Camp Half-Blood at the start of the novel. The Gray Sisters cryptically tell Percy a string of numbers, which Percy eventually realizes are the coordinates of Polyphemus’s island.

Hermes

The Greek messenger god, and the father of Luke. Hermes gives Percy supplies and encourages him to leave on an unsanctioned quest to find the Golden Fleece in the hopes that Percy will be able to get through to his son.

Hydra

A fearsome monster with regenerating heads whose life is tied to the Monster Donut franchise. The Hydra nearly kills Percy, Annabeth, and Tyson, but they are saved by Clarisse at the last moment.

The Laistrygonian Giants

The cannibalistic giants that infiltrate Percy’s school by claiming to be prospective students under the names Marrow Sucker, Skull Eater, and Joe Bob. They attempt to kill Percy and his fellow students with explosive dodgeballs but they are overpowered by Percy, Tyson, and Annabeth.

Matt Sloan

A bully from Percy’s school who targets Percy and Tyson. Sloan blames Percy after the Laistrygonian Giants destroy the gym.

The Oracle of Delphi

An entity that resides in the attic of the Big House at Camp Half-Blood, who delivers predictions of the future to aid demigods on their quests.

Party Ponies

Chiron’s wild centaur relatives.

Poseidon

The Greek god of the sea and the father of both Percy and Tyson. Poseidon aids his sons on their quest by sending the hippocampi (sea horses) to carry them across the ocean. At the end of the book, Poseidon invites Tyson to train in his underwater forge and sends Percy a letter ominously telling him to “brace himself.”

Rainbow

A hippocampus (a sea horse invented by Poseidon) who bonds with Tyson early in the heroes’ quest.

Sally Jackson

Percy’s loyal and loving mother who is unwaveringly devoted to her son’s safety.

Scylla

A fearsome sea-monster who, along with Charybdis, guards the entrance to the Sea of Monsters. She grabs Percy off of the CSS Birmingham, but he manages to escape her clutches.

Sirens

Sea nymphs whose enchanting song creates powerful hallucinations that lure sailors to their death. The Sirens almost manage to kill Annabeth, but Percy manages to save her.

Stymphalian Birds

Lethal birds with bronze beaks who interrupt the chariot race at the start of the book. Percy, Annabeth, and Tyson get rid of them by blasting Chiron’s music because they do not like noise.

Tantalus

A prisoner from the Fields of Punishment who is temporarily brought in to act as the activities director of Camp Half-Blood after Chiron is fired. He has an antagonistic relationship with Percy and gives him and his friends unjust punishments.

Thalia

The courageous and selfless daughter of Zeus who sacrificed her life to save Annabeth, Luke, and Grover before the events of the series began. Her spirit is contained within a pine tree on Half-Blood Hill, creating an invisible barrier that protects Camp Half-Blood from monsters. Thalia’s tree is poisoned at the start of the text and requires the healing powers of the Golden Fleece.

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