Stheno, the Bargain Mart was a front! You’re going native! Now, put down that ridiculous tray and help me kill this demigod.

–Euryale yelling at Stheno, in The Son of Neptune

Euryale was one of the three Gorgon sisters, the others being Medusa and Stheno. Despite having faded earlier, Gaea revived her.

Percy Jackson and the Olympians

The Lightning Thief

Medusa told Percy, Annabeth, and Grover that her two sisters had helped her in her business, but had passed on.

The Battle of the Labyrinth

On the quest through The Labyrinth, Tyson urged Briares to summon his brothers to help the unprotected Camp Half Blood. Briares told Tyson, Percy, Annabeth, and Grover that his immortal brothers did not exist anymore. Percy then recalled that Medusa's sisters were, also, forgotten immortals and they passed on.


Euryale from the UK cover of The Son of Neptune.

The Heroes of Olympus

The Son of Neptune

Euryale, along with her sister Stheno, had been repeatedly killed by Percy, but they just kept on reforming because Thanatos was unable to prevent monsters from coming back from the dead. She was determined to take revenge on Percy for vaporizing Medusa, who hadn't reformed yet. She scolded her sister for telling Percy the secret of Gorgon blood and for being too obsessed with her work.

During the assault on Camp Jupiter, Euryale and her sister attacked the giant eagles. They had both been killed by the end of the battle, possibly by Mrs. O'Leary.


Euryale was far more narrow minded than Stheno and crueler. She appeared to be the dominant sister as Stheno seemed nervous when she began to shout for not following her plans, and she always ordered Stheno around. Euryale was also smarter than Stheno but not more than Medusa.


  • According to Medusa in The Lightning Thief, Euryale and Stheno had both faded, yet, they appear in The Son of Neptune, meaning Gaea may have some way to bring back even faded beings.
  • Her name is pronounced like Muriel.
  • A genus of waterlily and species of bat are named after her.
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Enemy Monsters: Antaeus | Agrius and Oreius | Arachne | Cacus | Carthaginian Serpent | Charybdis and Scylla | Chimera | Chrysaor | Clazmonian Sow | Colchis Bulls | Echidna | Euryale | Geryon | Joe Bob | Kampê | Kekrops | Ladon | Lamia | Manticore | Medusa | Minotaur | Nanette | Nemean Lion | Polyphemus | Python | Sphinx | Stheno | Typhon | Trojan Sea Monster
Neutral Monsters: Carnivorous Sheep | Cerberus | Erymanthian Boar | Gray Sisters | Flesh-Eating Horse | Furies | Gryphon | Orthus | Skolopendra | Sybaris