The Eight Guardians of Terra were the first eight original Kaiju to inhabit Terra millions of years ago, some time after the formation of the planet. These eight Kaiju were all born from the great Tree of Life, the source of all of life's existence of Terra, and were each gifted with their own elemental attribute to keep the planet in balance.
Many years after the formation of the planet Earth (or Terra), an ancient, powerful artifact known as the Tree of Life grew from Terra's soil, harboring the power to give birth to powerful beings. The first creatures to be born from the tree would later become known as the Eight Guardians of Terra, eight extremely powerful beings who each carried a certain element in order to keep order and balance to all life on the planet.
Then, during the Cretaceous Period, two powerful and deadly space Kaiju, King Ghidorah and DesGhidorah attack Terra at the same time, resulting in the extinction of the dinosaurs and nearly all life on Terra. The Eight Guardians of Terra fought back against the two and successfully defeated them, driving a barely alive King Ghidorah back into space while DesGhidorah was sealed deep beneath the earth by Gigamoth.
Then around 77,000 years ago, when the First Civilizations fully colonized the planet, one of the members went rouge for unknown reasons and caused a mass extinction, resulting in only less than 10% of the human race to remain. The remaining members fought back against their own sibling and managed to place a seal on him before launching him into space to prevent him from rampaging further.
In order to prevent the extinction of the human race, the remaining seven members sacrificed their souls to the Tree of Life to restore the human population, trapping the guardians' souls in a state of limbo to look after humanity as well as other universes from beyond. Before they sacrificed themselves to the Tree of Life, the Guadrians used the last of their energy to create a new line of guardian kaiju to keep balance on Terra such as Mothra, Battra, Baragon, Manda, Varan, Dagahra and Ebirah.
At some point before the series, the remaining members of the Eight Guardians of Terra encountered Mavis Vermilion, the founder and first Guild Master of Fairy Tail and they began to work closely together in an unknown way.
According to the Shobijin, the Eight Guardians of Terra were responsible for defeating King Ghidorah and DesGhidorah when they both attacked Terra together and caused the extinction of the dinosaurs, driving King Ghidorah from Terra and sealing away DesGhidorah. 77,000 years ago, during the time the First Civilizations roamed the planet, one of the members went rouge for unknown reasons and caused another mass extinction more devastating than the one that killed off the dinosaurs, resulting in less than 10% of all human life to remain.
|Gigamoth||Kaiju of Earth||Active|
|Tornaq||Kaiju of Ice||Active|
|Gamera||Kaiju of Water||Active|
|Orikalkos||Kaiju of Air||Active|
|Irokus||Kaiju of Fire||Active|
|Raiga||Kaiju of Quintessence||Active|