Qulaesha

The Qulaesha were a group living deep underground of unknown composition. What is known about them, comes from various books and the occasional children's tale. As their home has never been found, it is impossible to verify these stories. However, similarities between sources from varying places do suggest a good chance of authenticity.
They were said to have originated from several smaller groups that each survived in their dark homelands. While initially they avoided each other just as they avoided any other threat, over time they began to actually cooperate. Eventually they joined up and made a unified base. This base was constructed in such a way that it granted them a great line of sight while remaining unnoticed, so that any predators could be easily avoided.
It was not just predators they had to fear, as warmongering groups would migrate through these darklands. Thanks to their numbers from joining, the Qulaesha managed to set up a good detection system. This let them avoid these as well. At the same time, they gathered resources from garbage dumps and any group that died against creatures.
However, there was a weakness to their detection system, one they had never anticipated. At the center of their base, an ancient red dragon swooped down. While their defenses let them hide, the dragon merely sneered at this feeble attempt. Instead of attacking or leaving, it chose to destroy all nearby escapes, guaranteeing that the Qulaesha would starve if they stayed in hiding.
Next, several armed groups approached, serving the dragon. They gave the Qulaesha a choice: Either gather gold for their wicked master, or burn to death. Thus the Qulaesha were forced into servitude. To guarantee their obedience, half their numbers were forced to stay near the dragon's lair, while the other half slaved away.
As the dragon's reign grew crueler, as did its loyal servants, the Qulaesha eventually realised there was no future for them if they stayed in servitude. Thus came the Qulaeshan Uprising. Some stories say they all died, others say they faked their deaths and escaped. Of course the fact that their story exists means that if true, they did survive.