Percy later wakes up. He learns that he is in Camp Half-Blood, which is a secret training camp for demigods. Percy has to live in the Hermes cabin because he does not know which god his father is. He is under the care of Luke Castellan, the cabin counselor (leader). During a game, the children of the war god Ares attack Percy. He is healed when he steps into a river. When Poseidon's trident appears above his head, Percy learns that he is Poseidon's son. After World War II, Poseidon, Hades and Zeus made an oath (promise) not to have any more children because they were too powerful. However, Poseidon broke the oath by having Percy.