When time had yet to begin, and the universe as we know it was simply a void of nothingness, the God of Darkness was born. The most ancient existence was followed by a sister, the Goddess of Light, who created the worlds, land, and all things living.
The God of Darkness assisted, crafting the oceans, magic, and all things necessary to support the Goddess of Light's work.
Neither god was inferior to the other, and through their work they created it- Gaia. The perfect world, and it's life.
Each god chose species they favored and granted them special power- authority.
The god of darkness chose the Proto-Daemon, the goddess of light chose the Proto-Humanoid.
After choosing the species they liked, they left. The two gods moved on to create more, to fulfill their desire to craft, and allow their creations to grow.
Billions of years pass. The Universe is incomprehensibly vast, populated with the most fantastical beings one can imagine. It is now that the two gods return to their first, and greatest creation: Gaia.
The Proto-Daemons have clawed their way to the top, and have evolved into the Demon Race. Their raw strength is unmatched, their faith in the god of darkness unwavering even in the billions of years where they were left.
The Proto-Humanoids became Humanity. Their nobility, numbers, and magical skill was unmatched by the demons, their faith was little compared to the demons in their god, but they were still strong, strong enough to lash out against the very race that they had cooperated with for billions of years.
Each God was enraged by the decisions the humans made, and sought individuals from one of their youngest worlds to act as ambassadors to their gods will.
The Goddess of Light chose a girl from Aither named Melody. She was pure, faithful to the goddess, and well meaning.
The God of Darkness chose a man from Earth named Cain. He was lonely, depressed, and had no idea the gods were real, yet was seen as the perfect vessel for the God of Darkness' will.
Thus, the Lords sent their saints to Gaia, to allow their journey to begin.