Gaea is the primordial god of the earth and the mother of the Titans and the Gigantes. During the time that Uranus was king of the known world, Gaea became unhappy with his rule after he cast her various children into the pits of Tartarus. As a result, she asked her children to overthrow him, but only her youngest child Kronos agreed to do it. After Kronos defeated his father and took the throne, Gaea was appalled when he took the same path as his father and tossed anything he deemed unfit into Tartarus. Gaea turned to her grandchildren, the gods, to defeat Kronos and they eventually did, splitting up the realms of the world as they seemed fit.
Gaea was unhappy with their rule and bore another group of children with Tartarus, called the Gigantes. Each Giant was specifically born to defeat one of the Olympians, but with the help of the gods' children, they eventually defeated the Giants and Gaea went into a deep sleep.
In The Heroes of Olympus series, Gaea once again returns as the main antagonist. Still angry with the way the gods rule the world, she made plans to once again destroy the gods, going as far back as World War II when the gods were fight amongst themselves. She used a young girl named Hazel Levesque, who had the power to raise precious metals from the Underworld, to bring the first of her children back. Her plans were delayed however when Hazel sacrificed herself in order to bury Alcyoneus back in the earth. This only delayed Gaea as her children began to rise one by one and took action after the events of the Second Olympian War.
Gaea is one of the most powerful beings in existence. Her realm of power is the earth itself and there are few places her influence doesn't touch, such as the sea and sky. However this power comes at a price, as Gaea is so powerful that she is rarely fully conscience and takes a long time to wake up. Even during The Heroes of Olympus series, she is not yet fully awake. Gaea is also somewhat manipulative, as she constantly visits the seven of the prophecy and plagues them with doubts about themselves. With the odds stacked against the demigods, only time will tell if Gaea will ever be truly defeated.
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