The Progenitors are the legendary first (and doctrine dictates only) species to evolve intelligence and technology to the level of space-flight without being genetically engineered by another species. They began the great chain of uplift from which all species owe their patron-client lineage. While revered by all races in galactic civilization, no specific information about them as a race survived in the Library after their disappearance billions of years ago.
Their remains were found by an Earth ship called the Streaker, which was promptly pursued for reasons unknown to the crew, leading to a five-way war over a planet called Kithrup.