Like her husband Zuras, Cybele is a second generation Eternal. Very little has been revealed about Cybele's past. She married Zuras, ruler of the Eternals of Earth, before the rise of the civilization of ancient Greece. Zuras and Cybele had one known child, Azura, who later took the name Thena. Although Cybele was the consort of Zuras, she evinced no interest in participating in the great events of Eternals history, such as their encounters with the Celestials. She lived with Zuras for a time and raised Thena, and today retains her maternal interest in Thena's welfare. However, Cybele never felt comfortable in the society of her fellow Eternals, and appears to have left their city of Olympia after Thena reached adulthood. Although Cybele was technically the queen of the Eternals by reason of her marriage to Zuras, she has never truly been interested m governing them, and, after Zuras's recent death, was content to let Thena become the new ruler of Earth's Eternals.
Cybele has always had a great interest in nature, and in the days of ancient Greece was often mistaken for the Earth goddess Gaea. Today she lives by herself in a forest in Colorado, using her psionic powers to prevent herself from being seen by human beings unless she wants them to see her