The Creator had created Impthus out of the very essence of light itself. And so do all of his fellow followers. The Athlran glow endlessly, no matter where they are. They have a pair of white wings and their form radiates bright light, as the High Heaven itself.
At the beginning of life, before the Living World was created, the Creator had created only Felenthur and Impthus, that he made them both as brothers. One with the heart of darkness and one with the heart of light. Impthus was given the High Heaven with the Orb of Light. While, Felenthur was given the scorching plains, where soon, he transformed the plains into the Burning Hell as soon as he managed to made a plea to the Creator. A plea which he asked to create an ally for him. Thus, the Demon Princess and Princesses were born into the Burning Hell.
They have no souls, but they live. They are formless, but they walked. They are unseen, but they reveals. They walk the dark plains, but they show the lights. And they were given a chance to choose side. And yet, they chose righteous. And that's the Farons. Creature that walks the void realm.
When running a new party, get around the question of plot density by having the first discovery to be a deck of fate, or whatever you call it. If you use a real deck, you should definitely stack it to have the desired outcome, which is to curse the party to attract weird things to happen and involve them. This should not be told to the players at the time, so that they won't just up and try to get themselves 'decursed'. Though quite why they would want to is beyond me.