Undercity (Taris)

Centuries prior to Taris's rise as a galactic center, the Taris Civil Authority initiated the construction of a planet-spanning city on the surface, expanding outward from a catacomb region below which would become the Promised Land. In time, a sewer system was established to connect the two cities, ensuring the maintenance of the infrastructure. Subsequently, the Lower City was erected above it, followed by the Middle City above that, and ultimately, the Upper City was built as the final surface layer, effectively blocking the sky and sunlight from reaching the lower levels. Sometime after the trade lanes shifted, specifically in 4156 BBY, the Rakghoul disease mysteriously infiltrated the Tarisian Undercity. This event led to the city's abandonment, and the sewer system fell into disrepair, eventually becoming overrun by Rakghouls and Gamorrean slavers, while still functioning as the planet's substructure.

The Galactic Republic abandoned Taris, causing the Tarisian industrialists to select their own sources of power, which unfortunately created toxic waste. A century later, this pollution poisoned and killed a majority of the oceanic plant and animal life, which resulted in widespread famine. The Tarisian elite then hoarded the remaining food and wealth, taking far more than they needed, while the poor were left to face starvation and death.

The impoverished citizens of Taris, enraged by the actions of the wealthy, initiated a rebellion, which marked the beginning of the Tarisian Civil War. Millions of innocent people perished and large sections of Taris were either destroyed or abandoned. It was during this period that the self-sufficient colony was lost to the Tarisians. The rebellion was ultimately suppressed, and the surviving, disarmed rebels were imprisoned. However, due to overcrowding in the jails, they were instead banished to the Undercity, with the threat of death preventing their return to the surface.

The Outcasts were trapped in their squalid, lightless, and rakghoul-infested prison. They never left it during their miserable lives, and they had little hope for the future of themselves or their children, with the exception of Rukil. Rukil was an elderly Outcast who devoted himself to studying and believing in the existence of the mythical Promised Land, a self-sustaining colony that had been stocked with supplies and droid attendants, but had long been forgotten by the rest of Taris. Rukil claimed that if they could find the location of the Promised Land, they could escape their wretched existence and live comfortably for the rest of their lives. However, most villagers did not believe in these stories, and they thought that they only served to give false hope.

The mechanical wilderness surrounding the Undercity village was extremely dangerous because of rakghouls, creatures that were part human and part beast. They seemed to exist only to attack nearby humans and infect them with the rakghoul disease. The Outcasts had to keep infected people away from the rest of the society because they would inevitably turn into rakghouls. The dangerous sewers in the Underlevels were full of rakghouls and Gamorrean slavers, who used the area as a base.

When the Republic lost the planet to the Mandalorians, the Taris Resistance briefly held out in the Lower City. However, they were later defeated and retreated to the Undercity so that they could escape aboard The Last Resort, which was based there near the Outcast village.

When Revan arrived in the Undercity, he was greeted by Shaleena, an Outcast living in the village. Shaleena told Revan to find and talk to the village leader, Gendar, and to talk to Rukil if he wanted to. Shaleena also told Revan about Rukil's stories of the Promised Land. Revan visited Gandar first, then immediately went to see Rukil.

At Rukil's request, the amnesiac Revan sought out the journals of Rukil's apprentice Malya, Rukil's father, and Rukil's grandfather while he was trapped on Taris during the Jedi Civil War. Rukil had reached the age of 100, having survived in the Undercity for a century. After Revan presented him with his findings, he pieced together the clues in the journals and finally discovered the location of the Promised Land. He shared this information with Gendar, the village leader, who said that although the journey would be long and dangerous, requiring them to cross rakghoul-infested territory, they had plenty of supplies. Faced with the choice of continuing their bleak, hopeless lives or pursuing the hope that the journals offered, the Outcasts set out for the Promised Land.

As a final act to help the Outcasts, Revan saved them from the rakghouls by giving a rakghoul serum vial (which he found on the remains of a Sith trooper) to Zelka Forn, a doctor in the Upper City. Forn was able to reproduce the serum and use it to cure the Outcasts of the disease. He also used it to cure another Republic soldier, who was later killed by rakghouls. The journey to the Promised Land was successful, but the building's generators, equipment, and possibly the droids were in ruins.

After several generations, the Outcasts were dying in the Promised Land from Rakghoul attacks, starvation and diseases. The Promised One led them upwards into the new sky filled Undercity and renamed themselves the Tarisians. This was in vain, however, as the Rakghoul serum became useless with the evolution of the Rakghouls, and no one knew how to improve it. There was even a sentient evolution of the Rakghouls into the Nekghouls, but unlike the Rakghouls, the Nekghouls couldn't spread infection. The last successful recording was made just days before the last generation died out from toxic waste, rendering them extinct like the rest of the population during the bombardment.

During the Cold War that followed the Great Galactic War, the Republic attempted to rebuild Taris in the hopes of defeating the Old Sith Empire. A Jedi recovered the lost history in both the Undercity and the Promised Land and gave it to a local Republic historian. He also obtained a Rakghoul serum vial from Pirates, who were found in Zelka Forn's long-abandoned second medical facility, where the Outcast village once stood. The serum was improved and mass-produced for a third time. Governor Saresh struggled to eliminate corruption in the military and civilian forces across Taris. Thanks to her efforts and dedication, the initiative was making more progress than it had in the previous decade. However, with the help of various members of the Empire, Gravus managed to stop the project, and Taris, particularly the Undercity, was occupied by Imperial Forces for an unknown period of time. In 3 ABY, much of the Undercity had been rebuilt by Human colonists, but it was never again a prison for banished criminals or overrun by rakghouls.

If the player chooses the dark side, Revan can sell the journals to Igear, a shopkeeper in the Undercity who destroys them out of jealousy. He wants to increase his own prestige and profit by making the settlers rely on his store. This dooms the Outcasts to remain in their village in the Undercity.

Furthermore, the player can follow Gurney's advice and give the rakghoul serum to Zax at the bounty office in Javyar's Cantina. If the player does this, the infected Outcasts will be forced to mutate into rakghouls, and the player will not be able to buy rakghoul serum from Zelka Forn, the doctor in the Upper City, at a low price.

It is unknown if the Undercity in the Old Republic era was the same as the one rebuilt in the final days of the Rise of the Empire era (in 1 BBY). However, in Star Wars: Empire at War, the land battle took place on only one level and looked quite new. It is possible that whatever was left of it after the bombardment was torn down and rebuilt by the Human colonists.