The Sebaceans are a fictional alien race from Farscape.
They are the core species of the Peacekeepers — a militaristic mercenary organization who will enforce the law of the lands they inhabit for a price. There are, however, non-military Sebacean settlements on various planets.
In the Farscape: The Peacekeeper Wars miniseries, it is implied that the Sebaceans were originally humans, taken from Earth tens of thousands of years ago. At the dawn of the Eidolons period of usefulness, they developed need of a guard for their effort toward peace. A race no one had quarrel with. A force to ensure harmony prevailed once negotiations had finished. The Eidolons took great care to choose a species no one had met before. They found a primitive race, barely clothed, far removed on the galaxy's outer spiral (likely a reference to the location of earth). Having brought some of them back to their homeworld of Arnessk, their evolution was accelerated with "generous alterations", until they became the Eidolons' trusted acolytes.
With the disappearance of the Eidolons from the galaxy 12,000 cycles before the Farscape setting, the Peacekeepers attempted to carry on. However, lacking the Eidolon's mediation abilities, they kept the peace the only way they could - at the muzzle of a weapon.
Although they have various internal differences, Sebaceans are so physically similar to humans as to be outwardly indistinguishable from them. They have a considerably longer lifespan than humans. Some Sebacean senses are sharper than those of humans, however, human smell and taste has been seen to detect rotten food that Sebaceans may not notice. This is counterbalanced by an extreme sensitivity to heat as Sebaceans lack the gland that regulates their body temperature under these conditions. They may suffer heat delirium if exposed to extreme temperatures for a prolonged time. If left untreated, heat delirium can lead to the "living death" — a state in which they have lost most of their higher brain functions and that most Sebaceans consider worse than death and for which they routinely euthanize patients.
The paraphoral nerve is an internal organ of the Sebaceans used to eliminate toxins from the body. In this sense it may be analogous to the human liver, or possibly the kidney. If it is damaged, death will occur within 50 to 60 arns. The only known treatment for a damaged paraphoral nerve is either a transplantation of a healthy organ from a compatible donor or a synthesized sample injected into the patient