Depending on who you talk to, The Blades of the Golden Sun were either the greatest warriors for Good the world has known or the most famous scam artists- who extorted money from people and countries to fight Evil that they created.
The order claimed it had mandates from the Gods that dictated their actions. They fought to stop Evil, or as they called it, The Tide of the Dark Night. Long ago, demons did invade the world. They are the Forces of the Many Flags did stop the Demons.
The order’s warriors managed to keep the force of the Dark Night at bay, never letting the monsters keep a foot hold for long. Eventually they discovered those who were minion or and shadowed (possessed) by Dark Night forces. They fell upon those utilizing their truth finding and darkness sensing. Their loses were great and their replacements few. While they stopped the Darkness, they could not keep society creaking forward.
The Order followed its own orders rather than the direction of Crowns and Lords (though they did follow the law). They helped those who they could. They were given gifts from grateful nobles and other personages. Countries and Imperial holdings gave them land grants to make sure the Blades always had a presence in their regions. Over the years, these began to add up to great wealth. The Blades, being international, were albe to act as a bank, brokerage house, and trade center first for their members, but later for anyone - especially merchants. Warriors or scam artists, either way they were a rich and powerful group from Imperial times.
Being rich and powerful, the Imperial throne saw them as a threat to its power. Eventually Emperor Coscious the Mad outlawed the order, citing acts of treason and heresy by the group. The Army marched against all their holdings. They killed defending themselves and their charges, their lands and treasure were seized, and all scrolls and books of their creation (being herretical and treasonous) were destroyed. The order was destroyed.
Or so the histories say. There are whispers of survivors. Those who managed to spirit away historical treasures, great works, weapons, and money. They are hiding in the catacombs of most cities. These survivors continued the Order in secret, recruiting new members suited to the secret society status it now had. The Group continues follow their divine mandates from the shadows, without interference from the crowns and lords.
Upon occasion, someone is seen with the Sun Swords doing some deed. These deeds are normally heroic, but some times just strange. However, they happen often enough to keep the legend alive.
Members were given training in religious, meditative, physical (akin to kung fu), combative (various weapons), and magical arts. The Sun Swords of The Blades of the Golden Sun were their distinctive weapons, possessing wonderous powers. These skills are far beyond any battle order known to “modern men”.