Luke Castellan
Luke is first introduced in The Lightning Thief as the 19-year-old counselor for the Hermes cabin. He was born the year 1986. While the rest of Percy's cabin mates complain about him because he is undetermined, Luke tries to make him feel at home, even stealing a toiletry bag for him. Luke first came to Camp Half-Blood when he was 14, alongside Thalia Grace, daughter of Zeus, and Annabeth Chase, daughter of Athena. Luke has a scar on his face, a relic from his battle with the dragon Ladon, guardian of the Garden of Hesperides, while on a quest. In The Last Olympian, it is shown that his mother attempted to become the Oracle of Delphi and has succumbed to the curse of Hades. Her crazed prophetic ramblings affected Luke greatly, and forced him to run away when he was nine. In The Battle of the Labyrinth, Luke's body becomes the vessel that harbors Kronos' essence.