The in-game description (retrieved from a wiki):
"The Obsidian Order of Eternity is a secret organization. It is shrouded in mystery, with even the Hand Occult having few clues about their origins. Some scholars have speculated that the order's members are a diverse group from all over Eora, brought together by their love of exploration, fierce battle and wondrous stories."
BTW, glad to hear the order will be kind of revived . Will donate my extra 8$ and become the cartographer of the ship