Olympian, Kronos mentions that Medusa has yet to reform. In the film adaptation, Medusa is portrayed by Uma Thurman. Jessica Parker Kennedy will portray Medusa in the TV show. Stheno – A Gorgon who is the sister of Medusa and Euryale. In The Lightning Thief, Medusa mentions that her sisters have faded from existence. In The Lost Hero, she is amongst the monsters who were brought back to life when the Doors of Death opened. Stheno is later found to be chasing Percy with her sister Euryale and is described by Percy as appearing as a dumpy old grandmother but with rooster feet and bronze boar tusk sticking out of the corners of her mouth. Percy manages to destroy the gorgons using the Little Tiber, but they later reform in time for the Battle of New Rome. Both are killed in the battle, one by Percy's pet hellhound Mrs. O'Leary. When the gorgons are destroyed the first time, they leave behind two vials of their blood, one of which is later used by Percy to destroy Phineas while the other heals his memories. Euryale – A Gorgon who is the sister of Medusa and Stheno. In The Lightning Thief, Medusa mentions that her sisters have faded from existence. In The Lost Hero, she is amongst the monsters who were brought back to life when the Doors of Death opened. Euryale is later found to be chasing Percy with her sister Stheno. Percy manages to destroy the gorgons using the Little Tiber, but they later reform in time for the Battle of New Rome. Both are killed in the battle, one by Percy's pet hellhound Mrs. O'Leary. When the gorgons are destroyed the first time, they leave behind two vials of their blood, one of which is later used by Percy to destroy Phineas while the other heals his memories. Gray Sisters – Women who share one eye and one tooth. In The Sea of Monsters, Percy, Annabeth, and Tyson run into the Gray Sisters who are in the form of three taxi drivers. During the Gray Sisters' argument, Percy manages to grab their eye and demand the location of which they had mentioned. They tell him 30, 31, 75, 12 which Percy didn't understand. He however gave the eye to Wasp and they drop the three off at Camp Half-Blood. Later at the campfire, Percy figures out that the numbers