The Decuri originated from the planet Decuu in the Decuu System. United in the Decuu Empire, they achieved lightspeed over 2,000 years ago, and colonised a few surrounding systems. After a meeting with the Fuller Republic, a war between the Decuu Empire and the Fuller Republic broke out. After 200 years of war with no real gains on either side, they signed a peace treaty. 300 years later, the Humans and the Decuri formed the Black Star Confederacy.
The Decuri got along quite nicely with the humans of the Confederacy, to the extent that there were many examples of children born to a Human and a Decuri parent. These half-breeds were commonly known as Hybrids.
Physically, Decuri had ashgrey skin, black hair, and red reflective or fluorescent eyes. Their growth cycle differed from Humans, with an early maturation and longer lifespan, and they often showed a physical strength greater than that of the average human. In all other aspects they were normal humans.
It had been theorized that the Decuri were an offshot of the Chiss species, but this was never proven.