From what was told to me, relations between Frater U.D. and the OS are not the best.
I'm pretty sure that the Ordo Saturni and the current Fraternitas Saturni are the result of a schism. I really don't know the background of it, though, but the OS seems to be the more outspoken of the two, at least on the internet.
I do know that the current headmaster of the OS is working on a book of his own detailing the Lodge's history and current curriculum.
Sounds interesting. This is definitely going on my radar.
«Recibe, ¡oh Lucifer! la sangre de esta víctima que sacrifico en tu honor.»