Gaea was one of the Elder Gods who materialized on Earth before any life appeared there. She and her brother Chthon inhabited Earth's land masses, affecting geological patterns.
However, the rest of the gods, following the example of Set, started eating each other, a process that turned all but Gaea into demons. Worried that they might menace Earth's organic life forms, Gaea summoned the Demiurge and "mated" with it, to give birth to her first son, the sun-god Atum, who, in its form of Demogorge the God-Eater, devoured all the demons, except those that escaped to other planes, such as Set and Chthon. Gaea then merged with the Earth itself, and dedicated herself to guiding evolution. Atum went to live in the Sun.
Millions of years later, Gaea decided to allow the dinosaurs to become extinct, so mammals would evolve in their place. This angered Set, who drew power from them. He made the dinosaurs try to hunt down all mammals, so Gaea summoned the Demogorge to deal with him. Their battle may have finished killing off the dinosaurs. In the end, Set was banished from Earth again.
Gaea protected Earth from the influence of Set, supporting the development of humanity over dinosaurs and leading the cosmic entities known as the Celestials to destroy a group of Serpent Men.
Thousands of years ago, when the second generation of gods began to appear on Earth, Gaea mated with many of them (under various different identities) thus becoming the "Mother-Goddess" mentioned in several myths. Under the name "Jord" she mated with Odin, who wanted a son who would be strong on Earth (not just in Asgard) and gave birth to Thor. However, Thor was not told the true identity of his mother until Gaea revealed it to him later on.
The Great Mother Danu was one of the deities of the Picts circa 18,500 BC. Valka was allegedly the son of Gaea. About 30,000 B.C, Valka achieved prominence, which lasted at least 12,000 years.
In 1000 AD, the Third Host of the Celestials occurred, during which the Space Gods informed they would return 1,000 years later to judge Earth's right to continue existing. While the pantheons prepared for war, Gaea planned a peaceful solution to the problem with many goddesses (among them Aman Sinaya for the Diwatas/Philippine gods, Amaterasu of the Amatsu-Kami/Shinto gods, Ameretat of the Yazatas/Zoroastrian gods, Ay of the Tenger/Mongolian gods, Chalchiuhtlique of the Teteoh/Aztec gods, Haumea of the Akua/Oceanic gods[65] (in fact herself), Hera of the Olympians/Graeco-Roman gods, Isis of the Ennead/Heliopolitans/Egyptian gods, Ixchel of the Ahau/Mayan gods, Julunggul of the Aboriginal Gods, Lada of the Dievas/Slavic/Russian gods, Lahamu of the Annunaki/Mesopotamian gods, Mahu of the Vodū/African gods, Mama Cocha of the Apu/Incan gods, Mielikki of the Jumala/Finnish gods, Morrigan of the Tuatha de Danaan/Celtic gods, Nelvanna of the Inua/Northern gods, Wiininwaa of the Manidoog/Native American gods, Xi Wangmu of the Xian/Taoist/Chinese gods, Ungnyeo of the Shin/Korean gods, Frigga and Sigyn of the Asgardians/Norse gods, and Saraswati, Parvati and Lakshmi of the Daevas/Hindu/Vedic gods.
For the next thousand years, they searched for humans representing mankind's highest ideals, to be offered to the Celestials as an offering. The goddesses placed the candidates in suspended animation, with their superhuman potential (legacy of the First Host) awakened: the Young Gods, a group of twelve humans, each representing one of mankind's achievements.
When the souls of all Asgardians (except Thor's) possessed the body of the Destroyer and attacked the Celestials, only to be defeated and scattered. Gaea then appeared with the Young Gods, and presented them to the Celestials as proof of man's worth to survive. They were accepted, and the Celestials left without destroying the Earth. Gaea, in the form of a dark-haired woman, then healed the wounded Thor, and explained the whole story to him. She also told him how he could restore the Asgardians' souls to their bodies with help from all the other Godheads, which he then went on to obtain. Gaea then went back to being 'one with the planet'.
Over the years, Gaea continues to grant power to many who call on her, from the ancient Sisters of Danu to the modern Ardina, Brother Nature, Clea, Dark Mairi, Doctor Strange, the Neurii, the Olympian Prometheus, and Topaz. Several years ago, Gaea was captured by the entity called Dormammu (who once held her prisoner until she channeled the life force of every being on Earth to banish him), but was freed by Doctor Strange and his lover, Clea.
She has also been directed opposition to threats such as Maelstrom. Her pain resulting from the harm humanity had done to Earth, nearly drove the mutant Humus Sapien to take the lives of all mankind.
She was captured by the extradimensional scientist Yandroth and forced to place a curse on the earliest Defenders, compelling them to gather to oppose threats to Earth. She continued to perpetuate this curse herself for a time, pleased to have even unwilling protectors, but she dissolved it after the Defenders became corrupt due to Yandroth's influence. She informed Nighthawk that he would have the power to summon them should the need arise.
During the Chaos War, Gaea was sought to be protected by the divine pantheons of Earth at all cost with the Shinto Sun Goddess Amaterasu sealing off the throne room of the Council of Elite to do so. When the Chaos King destroyed most of the divine realms of each pantheons, Gaea, with her daughter the Fire Goddess Pele summoned the remaining gods to Mt. Halemaumau for the last moments of farewell. There, Gaea revealed to Hercules that she is the true font of creation, the first being to form out of chaos and that she is the true power source of what the gods can do. She then instructs Hercules to embrace her daughter Pele as she teaches him to to become the God of Gods despite Athena's words that her time draws near with the Chaos King saying that Gaea should stop dreaming of creation and return to his night. Still, despite her weakened state, Gaea still managed to teach Hercules how to use the nigh-omnipotent powers within him and imbued him with her own powers allowing Hercules to destroy Athena in a single gesture.
Gaea was one third of the All-Mother of Asgard playing the role as the Mother as she ruled over Asgard alongside Freyja and Idunn in Odin's absence after the planetary attack by the Serpent. She later ruled Asgardia as a member of the All-Mother Trinity while having Loki serve as an agent of the trinity.
During her tenure, Gaea fell ill due to an unknown aliment affecting her physical form and her mystical garden and Sif took it upon herself to find a cure. While transporting Gaea and her garden to an asteroid space station for quarantine, she encountered Beta Ray Bill who had crashed his ship alongside another into the asteroid. Gaea was found inside the other ship, which turned out to be an ancient ark that collected one of every living creature across the galaxy and was rejuvenated by the variety of life around her. However, the ship combined and reconfigured the Stark technology on the asteroid, mutating Gaea into a monstrous form and attempting to collide with Earth before being convinced by Sif to relent. The ship crashed in Asgardia while fulling rejuvenating Gaea and her garden to their original state once more. Gaea later left the All-Mother Trinity when the group was disbanded after it was decided that Asgardia would leave Midgard because of the destruction of Broxton. She was ordered to remain on Midgard as it befitted her role as the Earth Mother.
As the War of the Realms ensued Gaea took care of Laussa, until Balder and his team arrived to keep the baby safe from the forces of the Dark Council.
In the aftermath of the war, Gaea attended the coronation of her son into the new All-Father.
