Gaea is the main antagonist in the Percy Jackson & the Heroes of Olympus series. She is the Mother Earth and one of the primordial gods. She is believed to be the 3rd to arise from Chaos. She first partnered with Ouranos and brought forth their children, the Titans. Later, she ordered the Titans to kill Ouranos for he had sent some of her children to Tartarus. After the death of Ouranos, she married Tartarus and brought forth their children, the Giants. Each giant was born to oppose a certain god. In the series, she tries to overthrow and kill the Gods and plans to rule and dominate the world. However, in the final fight, the 7 demigods defeat Gaea and lull her back to sleep, as she cannot die.