The Diogenes Society
The Diogenes Society is not a secret organization per se - it's just that its members typically prefer not to speak of it to outsiders, and so its existence is not widely known. Those who know of it typically refer to it as The Adventurer's Guild.
The Adventurer's Guild is indeed a fitting name for this group, which draws outstanding heroes and eccentrics of wildly varying vocations and ethnicities, who are all commonly drawn to adventure and great exploits. Some journey for money, fame, knowledge, or personal advancement and growth, but most merely out of the sheer addictive thrill of adventure.
