Hermetic Order of the Golden Dawn
This secret society of occultists is said to have members in every stratum of society. I have not managed to contact them, nor to find out who leads them, what resources or knowledge they have, etc.
But I am very interested in their rumored occult "systems" of magick. I have one source that claims they use arcane sigils to power their magick, and that those that wielded it were stamped out at the end of a prior primitive age. Apparently they have secret temples in London and contacts with the outside world. My source was killed a few weeks ago. All that once knew him claim to have no knowledge of him or who he was. They aren't able to recall him at all. It seems as though all trace of him was erased from their memories. His name was Samuel Mathers.