The Scarlet Brotherhood is both an independent nation in the Greyhawk setting and the secret organization that controls that nation’s government. They have spies across the world.
They believe in a Nazi-like racial (Suel) superiority; their leaders all have pale skin, blue eyes and blonde hair. Allegedly, they are cultivating some kind of breeding program in secret.
Their highest-ranking members tend to be monks, but assassins and fighters also populate their ranks.