ELPIS was the personified spirit (daimona) of hope. She and the other daimones were trapped in a jar by Zeus and entrusted to the care of the first woman Pandora. When she opened the vessel all of the spirits escaped except for Elpis (Hope) who remained behind to comfort mankind. Elpis was depicted as a young woman carrying flowers in her arms. Her opposite number was Moros, the spirit of hopelessness and doom.
Elpis, the Spirit of Hope, would not abandon humanity. Hope does not leave without being given permission. She can only be released by a child of man.
–The Last Olympian
History and Myths
Elpis is the spirit of hope and was the only good thing placed in Pandora's pithos. When Pandora opened the jar and unleashed its evil contents onto the world, Elpis was the only remaining benevolent spirit, staying with humanity so they would not give up hope.
In The Last Olympian, when Prometheus was enlisted to organize a truce between the demigods and Titans for a peaceful end to the fighting, he had Pandora's pithos in his possession. When Percy Jackson refused, Prometheus gave him the jar so that when he was ready to surrender, all he had to do was release her, symbolically "giving up hope." Though Percy was tempted to throughout the entire battle, Elpis was never released. In the end, Percy gave her to the goddess Hestia for safekeeping, because "hope survives best at the hearth." Hestia has since retained guardianship of the pithos.
Daimona of Hope and Expectation Goddess of Hope and Expectation Spirit of Hope