In the time before Time, where space was nothing but an empty expanse of energy, there were the Elder Gods: Laghrima the Being of Space, Fenell the Being of Time, Masuu the Being of Creation. The Elder Gods were all knowing and all seeing, they created our universe as a world for themselves, but grew bored of the nothingness. They created their Children to keep them company.
Laghrima and Fenell would fight to prevent their boredom, where as Masuu would be left with the care of the Children. The final fight of Laghrima and Fenell caused the Beginning, the creation of space and time as we know it. Masuu took advantage of this newly founded expanse of space dust and stars and created countless bright bodies of burning gas and rock. He found it beautiful, but unsafe for their Children.
Pantheon was created by Masuu for their children to play in safely for eternity. Masuu left the Children eventually as he soon grew tired of being a Space Nanny. The Children, after hundreds of thousands of millennia, grew tired of their playpin as well and decided to try create new toys.
The Children left Pantheon and descended to the rock nearest them, Earth where their arrival wiped out the monstrous beasts that had been inhabiting this place. They each claimed a corner of their new world and split their bodies into their children, the Gods.
When the Gods had set their roots they made human bodies out of clay, used their Blood to give them life, and sacrificed their ability of creation to give them intelligence.
At first humans were grateful and they worshipped their creators and built monoliths in their images. However, the blood the Gods used to make their new toys was too powerful for their clay bodies, It would destroy them after a Century or so. Driven mad by the threat of Death, Humans revolted against their creators, stopped worshipping the Gods and started waging war for the limited resources of their world.
The Gods, saddened by the supposed failings that were the humans, left Earth and returned to Pantheon. They swore on their Divinity to never set foot on Earth again, and to never create life again.
However after their return they noticed that when Humans died their energy took the form of their clay flesh and were sent to the Divine Playpin. Here humans reached their true potential, immortality, limitless strength, control over the elements, the power to bend wills, etc. The Gods were overjoyed their creations could make use of their divinity in Pantheon.
The God of Deathless War Nekkrimeh, proposed an Idea, to claim humans after death, impose their powers upon them, and see how strong they can get when are trained to harness their Power. However, the humans remaining on Earth had no idea of what had happened in Pantheon and still feared Death above all else.