There are five scientifically-recorded human senses: sight, sound, touch, taste, and smell. The sixth – supernatural perception – is far more difficult to pin down, if not nigh impossible through scientific means. And what science cannot define, it derides; thus, creatures long held to be of supernatural origin are dismissed by modern human society as myths.
The Guardian League would like to say otherwise. The organization consists entirely of supernatural beings. And they're putting ample time and effort into the protection of those humans who develop that precious sixth sense. They are sorely needed in this position, for it seems to be a universal law that where there is good present, there must exist evil as well. The Fallen are more than sufficient proof that such is the case. They are attempting to use the Talented humans' abilities in order to take over the planet, after all.