The Red Hand

In ancient times, before the establishment of the kingdom of Sarnios as a unified nation state, its current territory was divided between rival clans and city states. Although formally independent, the majority was under the influence of one of the four most powerful cities: Aniphera, Temphyra, Kaleidos and Thallas. These four confederacies were the main players in the region and were constantly engaged in warfare of varying intensity. Eventually, arguably the weakest faction of Thallas would come to dominate the others, growing over time in both wealth and power and taking the other's territory by what many perceive as an unbelievable string of favorable events spanning two centuries that would not be possible without direct favor from the heavens - or, as many believe to this day - an ominous dagger hiding in the bowels of society.
According to this conspiracy movement, when Thallas was crushed by its opponents, its ruler dethroned and its domain reduced to the walls of the impoverished city, the deposed Thalline king would move into the shadows and use the lack of attention of his victorious opponents to establish a secretive organization that would strike at his enemies with intrigue and crime whilst not drawing any attention on his diminished domain, ruled by a government supposedly puppeteered by the victors, but in truth controled by this underground society, which would come to be known as the Red Hand.
The Red Hand supposedly worked against its opponents from the shadows, manipulating them and slowly bending history to their will, until they would finally be undone and the city of Thallas would dominate most of the southern continental shoreline. Those who hold this conspiracy to be true believe that the Red Hand uses a belt with three notches as their secret symbol, indicating the three other ancient cities that were eventually sacked and conquered as a result of the organization's machinations, as revenge for the events that lead to the order's establishment.
That is where the Red Hand conspiracy theory stops being unified, as its believers attach events and even folk tales to this secretive organization at will. Some, for example, believe that the founder of the order made a pact with a demon that would give him eternal life and the power over shadows themselves in order to carry out his clandestine mission with guaranteed success; some believe that the Andarevian church was founded by the Red Hand to control the world through religion and praise the One Faith as liberators from their influence, whilst others see the One Faith, quoting its origin in secret organizations, as the tool of the Red Hand.
The only thing they still agree upon to this day are the belts with three notches on them denoting members of the organization. While many a brave would-be hero dared to investigate these claims, nobody has ever been able to get a glimpse into the mysterious organization to this day - and the extent of their influence on events across the entire continent, as well as their true intentions, remain a terrifying mystery to every truth-seeker to this very day.