In the series
Right before the start of World War II, the new Oracle gave the first Great Prophecy, claiming that a child of Zeus, Poseidon, or Hades would have to make a choice that would preserve or raze Olympus. Not wanting to take any chances, Zeus ordered that Hades' two children, Bianca and Nico di Angelo, be sent to Camp Half-Blood to be trained. Hearing of this, the Oracle advised Hades to hide his children quickly.
World War II
Already mistrusting of his brother, Hades asked his lover, Maria di Angelo, to follow him into the Underworld where he could protect their children and told her that there wasn't much time as Zeus' deadline had already passed a week ago. However, Maria didn't believe the gods would be so cruel as to kill their children and went upstairs to grab her purse. At that moment, Zeus sent down a bolt of lightning to kill the children. Hades managed to protect the children, but wasn't able to save Maria and cursed Zeus in his anger.
After Hades' children and Maria's body were taken away by the Furies, the current Oracle appeared before Hades. While Hades blamed the girl for his lover's death and threatened to destroy her, she countered saying the power of Delphi protects her and that she had warned him to hide the children sooner. Hades still blamed her as this all came about because of her prophecy. The Oracle remained unflinching until Hades claimed that even if he couldn't kill her, he could curse her. Hades claimed that as long as his children remained outcasts and he was forced to labor under her Great Prophecy, the spirit of the Oracle would never pass on to another host. Even after death, the spirit would never move on and would continue to speak prophecies until her body withered away to nothing but dust.
The Oracle's Curse
While the Oracle could no longer change bodies, after her death the only person to know this was Hades.
Twenty years after the Oracle's death, May Castellan attempted to take on the spirit of the Oracle of Delphi. While Chiron encouraged her, her lover Hermes protested against it as it seemed humanity had lost the power to hold the spirit. However, May wanted to host the Oracle and pushed for it knowing the risks. The process didn't take however and May was cursed with horrible visions of the future about her son and small occasions where she would talk about his fate in a crazed manner.
The body of the Oracle continued to remain in Camp Half-Blood's attic and no one else was allowed to try and take on the spirit.
The Oracle of Delphi first appeared when Percy Jackson was told by Chiron to get a prophecy so he could go on a quest. Luke Castellan explained that there hadn't been a quest since his own quest two years ago failed. The Oracle had told Chiron that Annabeth couldn't go on a quest until someone special arrived as well, leading Annabeth to think anyone new to camp could be the omen she had been waiting for.
Chiron told Percy to go get a prophecy from the Oracle as events were starting to become clear to him after he learned of Percy's parentage. Percy climbed to the Big House Attic and found the decomposing corpse of the long dead Oracle. However, when he asked her what was his destiny, the Oracle began to come to life and showed a vision of Gabe Ugliano and his friends playing poker as she spoke of a prophecy telling him to go west and face the god who has turned. While the last line of the prophecy made it sound like Percy would fail, Chiron told him prophecies usually had double meanings and to not dwell on them too much. As events unfold, Percy regularly looked back on the words of the Oracle as the events she spoke of began to pass.
While the Oracle didn't appear, Clarisse La Rue was allowed to be given a prophecy by the current head of the camp, Tantalus. This is most likely because Annabeth Chase and Percy devised the plan for a quest, and Chiron had been fired. Clarisse was given a quest to search for the Golden Fleece located in the Sea of Monsters.
When Percy returns to Camp Half-Blood after Annabeth had been captured by the manticore, he confronted the Oracle and asked her to give him a prophecy to allow him to find Annabeth. When she remained unmoving, Percy became angry, saying he would find a way to save her himself. After a game of Capture the Flag between the campers of Camp Half-Blood and the Hunters of Artemis, a fight began between Thalia Grace and Percy. Before things could escalate any more, Percy called off his attack when he saw the Oracle walking toward one of the Hunters, Zoë Nightshade. She gave the girl a prophecy in the vision of her maiden, Artemis, chained to rocks to find her and that she would only succeed if Hunters and camper work together. After the Oracle became still once again, Grover and Percy were elected to carry her back to the attic. (Percy mentioned "that probably doesn't mean they are the most popular.") Percy knocked her head, climbing the stairs back up to the attic and checked for broken bones.
Once again, the Oracle wasn't seen, but she gave Annabeth a prophecy so that she could travel into the Labyrinth and find the inventor, Daedalus. The prophecy told her that she would lose a love to something worse than death. Annabeth avoided mentioning the last line when Chiron asked about it; claiming she had forgotten the line.
|“||I forsee the future. I cannot change it.||”|
–The old Oracle
When Percy returned to camp after spending some time with Poseidon in Atlantis, he gave Chiron the message that he was ready for the Great Prophecy. Annabeth Chase and Percy went up to the attic and Percy questioned why she was dead. Annabeth however held herself back and asked the Oracle for the Great Prophecy. Percy expected something amazing to happen, but instead Annabeth grabbed a small scroll from around her necklace.
Percy had several visions of the Oracle in the past, seeing how the spirit was trapped in her current body forever. He was shown a vision of when May Castellan tried to take in the spirit, only for her to go insane when Nico had taken him to see her earlier before the battle. This curse, was because of Hades, who had said, "I swear, as long as my children remain outcasts, as long as I labor under the curse of your Great Prophecy, the Oracle of Delphi will never have another mortal host. You will never rest in peace. No other will take your place. Your body will wither and die, and still the Oracle's spirit will be locked inside you. You will speak your bitter prophecies until you crumble to nothing. The Oracle will die with you!"
After the Battle of Manhattan, Rachel took Percy's pegasus, Blackjack, back to Camp Half-Blood. As Hades' curse was lifed, Rachel took on the spirit of the Oracle successfully and the old Oracle completely died.
The power the Oracle uses to foretell the future and protect herself originates from the earth at Delphi. If that magic is blocked, the Oracle, Apollo, and anyone who depends on them for the power of prophecy loses the ability to predict the future.
- Prophecy: The Oracle had the power to speak the prophecies of Apollo. The power the Oracle used to foretell the future originates from the earth at Delphi.
- Divine Protection (limited): The Oracle was protected from even the gods, so much so that even Hades was unable to kill the Oracle, though he could curse her.
Despite not appearing in the initial movie, the Oracle appears in the second installment of the Percy Jackson film series. She shows Percy the story of Kronos and sends him on his quest.
- When a demigod went to visit the Oracle, the experience was sometimes so traumatizing that they sometimes returned insane, went into a coma, or died from the realistic images.