- "Remember, if you get your hands on that Rakghoul serum, take it to Zax in the Lower City Bounty Office. He'll make it worth your while."
- ―Gurney to Revan on the Rakghoul serum
During the Jedi Civil War a sample of the serum was created by Republic scientists and then replicated a few thousand times to cure the Outcasts during the Republic's restoration of the planet. The Republic had a base in the Upper City as the center of restoration as well as the location where the scientist perfected the cure. However, the Sith armada had taken notice of the planet and invaded. After driving the Republic out, they established the base to be their own. The Sith troopers used the samples of the Rakghoul serum for patrolling in the Undercity, for their search of the crashed Republic escaped pods of the destroyed Endar Spire. The Sith had so many encounters with the Rakghouls that they ran out of serum by the time Revan entered the Undercity, although some troopers who were killed still had serum samples on their corpses.
During his quest to leave Taris, Revan found a sample of serum on the corpse of a dead Sith trooper and used it to cure two infected Outcasts and then a infected Republic soldier before turning it over to Zelka Forn, the Upper City doctor. He was able to copy it hundreds of times and gave a large amount to the Outcasts' healer Esala and it was used to treat the infected outcast during their journey to the Promised Land. When they reached the Promised Land the Rakghouls continued to attack them in which they where forced to use more of the serum. Several generations after the Destruction of Taris, the Rakghouls evolved to be immune to the serum, but like the Sith troopers before them, some Outcasts still had serum samples on their corpses after their eventual extinction.
By 3,641 BBY, the rakghoul serum was rediscovered by pirates who presumably found a sample on a corpse of an Outcast and where persuaded to give it to a Republic doctor. Through the three hundred and fifteen years since the Jedi Civil War had ended, the virus gradually become mutated, making the serum useless. Therefore, someone had to be purposely infected so that the antibodies could be synthesized into a new, improved serum. The intentional infection was performed and the serum was altered, used on the tester and for a third time produced in mass quantities.
Behind the scenesEdit
The player can, for 1000 credits, sell the Rakghoul Serum to Zax in the Lower City bounty office. If the player's persuade skill is sufficiently high, they can convince Zax to pay 1500 credits instead.