Just as Prometheans are creations of the mystical science of alchemy, so are there alchemists who study the rest of the field. Unfortunately for the Created, the ones who study them tend to be either the kind desperate or power-hungry enough to ignore the fact that Transmutations and the other superhuman traits of the Promethean condition make them very dangerous - and cold enough to not care that in order to get at the rich source of Pyros and Vitriol that Prometheans are, they will have to victimize a sentient being.
Sometimes known as "the Insatiate" by their saner colleagues, the alchemists who hunt Prometheans are generally driven by hatred of an element of their humanity: they want to never die, or to want for nothing, or fear other humans. As a result, insatiates are notorious for the mutative experiments they perform on themselves, twisting them into something both more and less than human, even with Dread Powers that resemble those of Pandoran mutations. Their abuse of the Divine Fire also twists their minds, meaning that many alchemists are usually unstable to a greater or lesser degree. Unfortunately for the Created, the Insatiate are still human, which means they desire company who understand and comfort them-hence the number of alchemical guilds that dwell in the world, many of whom formed for the express purpose of hunting the Created for the resources they need.