This is hopefully the most detailed I'm gonna get, and I'm still trying to keep prep as minimal as possible. It's got storylines and ideas I've been sitting on for quite a while now, so it's pleasing for me to see the world creation and history combine into whatever the hell this is. Hope it makes sense and is a logical evolution of religious thought that sets up some decent factions for the players to tangle with.
THE MAIN RELIGIONS & BELIEFS OF THAUMATRIA
If there is a creator of the universe, they are a distant, unknowable entity that has never answered the questions of those it brought into being. Gods, monsters, and sentient beings have all called out to it, but have only ever been answered with silence. Who or whatever they are, they brought into being the universe and populated it with sentient creatures of varying degrees of power, their number increasing with their weakness, and scattered them across the stars on distant worlds.
One such world is Arkha. Orbited by the two moons, it is the third world of a planetary system around a single sun it shares with five other planets. This is your home.
It is said that in the beginning the Arkharnen lived side by side with humans in a sacred land simply called the Garden, but in their eagerness to emulate the wonder of the gods, humans stole the secrets of creation magic when it was not theirs to take. The Arkharnen forgave them, and tried to teach them the correct methods of its use; but the frailties of the human body could not handle such power, and their creations were poisoned by human’s mortality. It is from these mistakes that the Jugger Behem were born, monstrous manifestations of suffering that the Arkharnen were forced to exile beyond the realms of existence. Eventually the Arkharnen forbade the practice among humans, but it was too late; when they were found to be working magic in secret, they were cast out and the Arharnen removed themselves from direct contact with them for fear of greater theft. The Garden was abandoned and forsaken, and sealed off from the world.
The Leviathans were simply too great and powerful to be defeated by the sword; only the arcane powers of the sorcerer-kings could hold them at bay. Eventually the remnants of the human kingdoms fled across the narrow seas to a new land free from the presence of the Jugger Behem, and erected thaumaturgical defences that stopped the Leviathans from crossing. The descendants of the sorcerer-kings and their families formed Thaumatrian Empire, and worked together to protect all their peoples against further depredations of the Leviathans.
Some still chose to practice appeasement of the Jugger Behem, but such practices are publicly reviled and shunned. Secret cults still gather to practice sacrificial acts in seclusion, and are still manipulated by one or more of the monstrous gods. Their aims are unclear, though the suffering of all peoples seems to be their goal, and it is said that they work towards opening a permanent rift between this world and theirs. At times of solar eclipse monstrous beings do manage to cross over, and they always seek out practitioners of thaumaturgy with the intent to kill them. Analysis of these astronomical events led to the rise of Astromancy, in order to predict the coming of more Jugger Behem.