Their history begins roughly twenty seven thousand years ago, when a race called the Eidelons were trying to bring peace and order to the universe. However they were often met with aggression and violence but being peaceful they were unable to defend themselves. So they traveled to the edge of the galaxy and discovered a primitive race (Terrans) and found them to be extremely adaptable. Having made their choice, the Eidelons made alterations to the DNA of those they took back with them and created the Sebaceans.
From their actions alongside the Eidelons, they earned the name Peacekeepers. Several thousand years ago, the Eidelons disappeared and soon, without the guidance of the Eidelons, the Peacekeepers took to keeping the peace the only way they knew how - at the muzzle of a weapon.
Despite most Sebaceans being Peacekeepers there is a breakaway faction that resides in the unexplored region of space (this faction presumably formed long after the disappearance of the Eidelons), that is neutral in terms of politics between the Scarrans and Peacekeepers, and prefers isolation from both.
Though externally identical to humans, Sebaceans differ from them in various ways: for instance, above a certain temperature (40 or 55°C), they have an extreme intolerance for heat that sends them into a permanently vegetative state. Another feature is the ability to "pause" pregnancy for up to seven years (only Command Carrier-born Peacekeeper females are able to do this).
Sebaceans are capable of interbreeding with other races such as Luxans and Scarrans. However, the practice is normally frowned upon due to a doctrine of racial purity,especially among the Peacekeepers. Few Hybrids ever make it to adulthood due to death at Peacekeeper hands or conflicting aspects of their dual parentage. The few exceptions include Peacekeeper commander Scorpious (a Scarran Sebacean hybrid) and Ka Jothee (a Luxan/Sebacean hybrid). Despite regular checks, it is noted by the Peacekeepers that the number of Hybrids being born is on the increase.
The PeacekeepersEditThrough the decades, they developed into a mercenary protection force in which planets or even star systems would bid for their military services. However, once under the protection of the Peacekeepers, they are often duped into a more permanent arrangement, sometimes ending in the world(s) being totally handed over to the Peacekeepers. This essentially makes the Peacekeepers similar in a way to mankind's many mafias.
Although originally comprised of Sebaceans, the Peacekeeper Corps has expanded to include various other species (though whether or not these species volunteer or are forcibly incorporated is not clear). The Peacekeepers and the Luxan worlds recently entered into a defense agreement to present the largest possible show of strength in peace negotiations with the Scarrans.