So, the Society of Ouroboros. They are a major recurring villain organization across the five games I've played. Old, powerful, serve an as yet unknown 'Grandmaster'. Overall goals are unknown, but they definitely possess a lot of advanced knowledge of science and magic, that no one else except maybe the Church possesses. In particular, they seem to know a lot about the 'Sept-Terrions', divine relics from the prior age of civilization that are basically Infinity Stones, and have been lost for over a millenia.
Now, in Trails to Azure, one of the late game boss fights is with Campanella, one of the major members of Ouroboros. He is a cryptic trickster, so talking with him is almost as infuriating as fighting him ( note: his fight is *the worst in the entire franchise so far*, there are harder enemies but none more carefully designed to be obnoxious, ahem ). However, one line of his stood out to me: amidst his cryptic babble, he said something along the lines of 'humanity will be tested'. Now, in itself that doesn't mean much. . . except I have seen characters in the series elsewhere say something sort of like that before, talking about a 'test' for humanity.
Specifically, two of the Divine Beasts we have encountered, who are basically heavenly servants sent to earth by Aidios along with the Sept-Terrions, who are sworn to some purpose connected with said relics. Each of which takes the form of a different animal, and is connected to a different Sept-Terrion, has been around for at least the past 1200 years, and possesses unearthly knowledge about unearthly forces.
Which got me to thinking about the Society of Ouroboros, its name, and its symbol, which is a big tablet of seven gems *surrounded by a giant snake*. Which, if my theory is correct, basically means the 'Grandmaster of Ouroboros' is barely secret at all, but frickin' signed his name and posted his picture. Who is the Grandmaster? Its one of the seven Divine Beasts, a divine serpent by the name Ouroboros. And its been guiding a Society of followers, providing them with 'forbidden' knowledge for centuries, either in rebellion against its ordained role as a Divine Beast, or perhaps in keeping with it in some weird and possibly distorted way.