From Introduction:
When the Monster King ruled from atop his throne of skulls, the world amassed its armies to send against his might. And so he, in turn, sent seven evil harpies to spread his plagues across the lands that dared to defy him. Or so the legend goes. In service to their liege, these villains spread misery and misfortune through the ranks of his enemies, but though they brought him many victories, even they could not save his kingdom. Scribes are prone to exaggeration when they are afraid, so records of that time cannot always be trusted. But if these plague harpies were even half as terrifying as the ancient panegyrics say, then such fear was warranted.
And yet, all things come to an end. When the Monster King was finally defeated, his harpies did not look to his successors. They did not carry his legacy with them into the future. Instead, they became mercenaries, selling their skills to whatever evil lord could pay their price. Though often hired to conduct assassinations, they became just as good at kidnapping, and even better terrorists. Over long decades, they grew in infamy as they completed ever more daring and gruesome assignments.
But they too, fell, one by one, like their master before them. Some in battle, some killed by questing heroes or vigilant wizards. Perhaps some were even killed by other monsters. The sages say that six are dead, and now there is only one left, but how can they be sure? That there were only seven to begin with is just a rumour.
And what became of all the wealth they amassed? Their skills did not come cheap. But no one knows what they spent the wages of their sins on. Or at least no civilized human knows, not even those sages so certain of their histories. Perhaps those treasure hoards are still out there, somewhere, just waiting for a band of dungeon robbers to find them?