Perhaps the answer is closer to home than many people realize.
We often focus on the secret societies of negative influence. However, perhaps there are a great many more secret orders… Blood lines that the ones currently in power wish to suppress and destroy.
It wasn't that long ago when knowledge was very much a tribal thing. Not only was it that you learned from your tribe, but you had difficulty knowing just what another tribe did. Before widespread state education and the industrial revolution focusing on the core sciences, "magic" was alive and well in the sense that things could be taught without having to overcome a nearly insurmountable barrier of skepticism. People weren't nearly as apt to believe they understood everything about how the world worked.
Entire orders of alien descendents could be hiding in plain sight simply because the culture never really takes the topic seriously. Everything is a game.