Rey

The Rey are a humanoid species native to the planet Gullrey. 
They consider themselves superior to the Gullians, with whom they share their homeworld. The Rey once enslaved the Gullians, but eventually gave them limited rights in the early-26th century. However, Rey sympathetic to the Gullians began protesting with them to grant the Gullians full rights. Eventually, these protests exploded into a full Civil War.