Long ago, there were three great and powerful deities. They loved helping people more than anything else, but they each had different and conflicting methods.
Uriel felt that biology was the most supreme form of technology. Thus, she would help organisms evolve and grow stronger in the way that she though was the most natural. As long as they asked for her help, she wouldn’t hesitate to begin radically altering their genes in excruciatingly painful experiments.
Azrael was the opposite. He always felt disgusted by organic lifeforms and believed that there was a sublime beauty in machinery. From gears and steam engines to nanites, he would often create mechanical organisms, artificial intelligences and virtual realities in order to bless his followers.
Sariel thought that the only way to truly help anyone become stronger, was to teach them the ways of magic. Through the manipulation of mana, it was possible to accomplish anything one desired. Whether someone was willing to put forth the effort to improve themselves was another matter altogether.
The three of them were mighty on their own, but when they fused their souls and bodies together, they formed a being of immense power. That deity possessed the combined knowledge of all three and lost their former individual prejudices.
In that brief state of enlightenment, they realized something that so many other Gods and Goddesses had already understood… Even eternity cannot last forever.
Everything is cyclical. Eventually, their godly bodies would fade and even their souls would need to be renewed or refreshed in order to survive. They would lose their memories and reincarnate innumerable times before regaining their former glory.
A single life as a human or a similar lesser being, would merely last a few decades, possibly centuries. Compared to the eons that they had experienced as deities, thousands of incarnations could pass in the time that they would typically use to take a short nap.
When Uriel, Azrael and Sariel returned to their usual forms, they were filled with a sense of impending doom. They witnessed their own demise and knew that their complacency had caused their own downfall.
Thus, they decided to prepare legacies for themselves. Magical treasures, mystical artifacts, cultivation techniques, mysterious technologies, even godlike avatars.
Their goal was to give their future selves a chance to rise again from their own ashes, becoming more powerful than ever before. The legacies were scattered across the many universes, some were hidden in the Chaotic Void.