The worship of Nehemion the creator god is a relatively (as far as religions go) new development. After the collapse of the empire, an unnamed prophet declared that the world was suffering because mankind had been seduced into the worship of demons as gods. There was only one god and he was jealous and angered by his creations fickle nature. The prophet traveled across all the lands of the empire preaching utter submission to this new deity that he might perhaps spare them the torment they had brought on themselves. This message of doom was widely received in the chaotic and lawless times immediately after the fall of the empire.
As more people declared their allegiance to Nehemion and his temple, the prophet established himself in the City of Massadeh and formed the Holy Synod, a council of the most fanatically devout adherents that served to direct their ever growing flock. After only a few years, the number of Nehemiotes in the city grew so much that they effectively supplanted the original population and installed the Synod as the cities ruling council.
Now the Temple of Nehemion makes it its mission to spread its message as far as possible, worshippers of Nehemion can be found all across the world, but they are most prevalent in southern Osretia and parts of Alemannia.