Just something I drummed up for Balthazarr's Nova Europa setting; his game uses GURPs, but these are fluff concepts that can work in any sufficiently over-the top RPG. In fact, I may adapt several of them to use in my own Maelstrom setting,
Bermudan Sky Pirates
The "Bermudan Triangle" is a much-feared region where hundreds of vessels have disappeared- but not myseriously, for everyone knows the legend of Maxwell Morgan's fearsome band of raiders- how he stole a nest of Pterodactyl eggs from a research vessel bound back to the states, then raised and bred them to give his band of cutthroats a way to take to the skies. The villanous Maxwell is said to have met his end at the hands of a would-be victim who turned out to be an expert marksman, but his son Matthew has proven just as merciless.
Though their violent ways are undeniable, some speculate that the actions Morgan's Marauders are be driven by simple greed. There are men in the region who claim to have come from lost ships, and say that their vessels were lost not to men but to far stranger phenomena. And several pieces of archeological evidence uncovered within the past century have indicated that within the Triangle may lie a long-lost secret: The city known as Atlantis. . .
Servants of Valhalla
It turns out that certain sections of Norse Mythology are highly accurate but oft-misinterpreted descriptions of the cosmos. This is especially true for the sections regarding Valhalla, a realm of eternal festivities where warriors struck down in battle are brought to feast and fight without end. This is true, but what most fail to realize is that valhalla is another world in the sense that it is a different planet- one where the losing side in a war began to recruit and augment warriors from species on other planets. It wasn't enough, and that side lost the war in the 14th century- but the descendants of the victors have rediscovered the recruitment facility on the far side of our moon, and reprogrammed the Valkyrie-type recruitment cyborgs; they couldn't remove the moral code about only recruiting warriors who would otherwise perish, but nothing in the programming said that Valkyries couldn't be the cause of this state. . .
Aztec Blood Gods
While the actions of Spain's Conquistadores were not truly the undoing of the empire, those beyond the shelter of hidden cities such as El Dorado faced conquest and enslavement at best. Wracked by plague and facing wolves at the door, the leaders of these regions turned to ritual techniques society had forbidden in ages past- rather than simply dealing in lifeblood as a merchant deals in coin, they became avatars of the source of their power, and in doing so inherited its hunger for life.
From that time onwards, they have ruled over the central Americas in secret. From that time onward, their hatred for their brethren in the Hidden Cities who abandoned them to their fate has grown ever stronger, fueling a centuries-long secret civil war. From that time onward, they have assured the prosperity of their own people, but at a terrible price.
For from that time onward, they have been the most powerful vampires in the world.
The Tokugawa Shogunate
Their current obsession with cute cartoons and underwear makes it easy to forget that the Japanese used to be one of the fiercest peoples on earth. What if its government had held on to its "Sakoku" policy of isolation, rather than dropping it in the mid-19th century? An island nation ruled with an iron fist, from which none ever enter or leave. . .at least, so they say.
In reality, Japan's leaders are subtly active in the world abroad through a vast and highly secret network of spies. Though many intelligence agencies have heard rumors of the network's existence, few have the slightest idea who they report to. The shogunate's agents are the modern-day incarnation of the shinobi, hiding in plain sight and viewing death as the only honorable penalty for faliure. Those who uncover the truth will never know true security, for anyone and everyone could be an agent of the enemy.
Huntsmen of Herne
Some say that they are the Druidic order reborn- that the ways of the old celtic magicians have been rediscovered, that this secret organization seeks to reestablish the connection between man and the spirits of nature.
Others say that they are a death cult, assassins united by their pursuit of a supernatural means to visit death upon whomever a given member of the group selects.
Both are right. After centuries of absence, the Wild Hunt rides again- baying hounds led by black figures astride wild horses, racing hell-bent over oceans and betweenn skyscrapers in pursuit of the poor soul who until now had proven himself beyond the reach of his enemies.