Great Cleansing
The Great Cleansing was a devastating war of mass destruction that was waged some time in 350 BBY, on the world of Fyodos.
For centuries, the Galidyn coexisted with the Fyodoi, the Human colonists of Fyodos. However, in 350 BBY, the Fyodoi began to war amongst themselves - this war would become known as the Great Cleansing. Their advanced technology ravaged the planet, scorching the surface, and destroyed the Human societies. The majority of the Galidyn escaped the slaughter by retreating into underground caves and hibernating for almost two centuries. After the war ended, the surviving Humans abandoned the ruins of their once-great cities, and shunned all technology completely. This caused them to eventually regress to a primitive technological level.
The Galidyn initially attempted to reconcile with the Humans, and bring them back into society, but the Fyodoi had begun to regard them as technology-worshiping monsters. Though they felt pity for the Fyodoi, they decided to leave them alone.