List of characters in the Camp Half-Blood series
Oracle of Delphi - Apollo's Oracle of Delphi used to reside in the mummified remains of its host until its power was transferred to Rachel Elizabeth Dare in The Last Olympian. The Oracle's power originally passed from the deceased oracle to a newly chosen oracle; however, at the end of the second world war, the oracle gave a Great Prophecy predicting a child of the Big Three (Zeus, Poseidon, and Hades) would determine whether or not the gods would be preserved or destroyed. Using this information, the Big Three entered a pact in which none could continue to sire heroes. Before this, Hades bore two young children, Nico di Angelo and Bianca di Angelo. Zeus, fearing that either were the children of the prophecy, destroyed the hotel where the di Angelos lived with his master bolt, killing Maria di Angelo, Hades' lover. In revenge, Hades cursed the Oracle to ensure that the power of the Oracle of Delphi would not pass on to somebody else in hopes that it would soon return to the dust along with its  prison. After the Battle of Manhattan in which Hades and Nico successfully assist in the defense of Mount Olympus, Zeus honors the Lord of the Dead. In response to his newfound respect from the other gods, he lifts the curse, allowing the Oracle's power to pass on into Rachel Elizabeth Dare, the last Oracle.