Duel in the Jedi Temple ruins

In 3643 BBY, during the Cold War between the Galactic Republic and the Sith Empire, a young Jedi Knight was sent to the Republic capital of Coruscant by the Jedi Council. The Knight, who was the former apprentice of Jedi Master Orgus Din, and the astromech droid T7-O1 tried to rescue Doctor Eli Tarnis from members of the Black Sun criminal syndicate when the scientist was kidnapped from the Senate Building, and the pair learned that Tarnis had been taken to the gang's territory.

However, when the Knight and T7-O1 raided Black Sun's headquarters to find Tarnis, the two discovered that the doctor was in fact a Sith Lord who had been masquerading as a Republic scientist. Tarnis had stolen the Planet Prison superweapon, a device that supercharged a planet's atmosphere and turned it into an enormous ion cannon, and he now planned to activate it on Coruscant. Teaming up with the Padawan Kira Carsen, the Knight tracked Tarnis to the territory of the paramilitary Justicars' Brigade, and learned that Tarnis had tricked the project research team into bringing him the real prototype before murdering them. From a dying scientist named Jonkan, the two Jedi learned that the device needed time to charge up to full capacity, and that it generated immense amounts of heat while doing so. Thanks to Jonkan's information, the Knight and Carsen were able to locate the device in the ruins of the Jedi Temple, which had been destroyed in the Sacking of Coruscant by the Empire over ten years earlier.

Since the fastest way to reach the ruins of the Temple was through The Works, the industrial sector of the planet, Carsen led the Knight to the closest access elevator in the Justicars' Sector. Within The Works, the two Jedi fought their way through rogue droids and Imperial forces in order to venture into the Temple.

Deep within the Temple, the duo found the remains of the High Council Chamber, which was guarded by almost a dozen Imperial saboteurs. After defeating the surprised Imperials, the duo found Tarnis in the chamber itself amidst the tangle of wires, computers, and generators that formed the Planet Prison. The Sith Lord was standing before a holoterminal, deep in discussion with four figures: a Pureblood Sith, a masked humanoid figure, a short robed Human, and a red-robed older Human. The older man, clearly the leader of the four, praised Tarnis on his work, and astonished the two Jedi by calling Tarnis his son. As the Knight and Carsen stormed into the room and confronted him, Tarnis revealed to the intruders the identity of his red-robed father: Darth Angral, the architect of the Sacking of Coruscant, and a personal enemy of the Knight's Master. Tarnis also informed the pair the Planet Prison was minutes away from being ready to fire, and that they would not be able to stop it.

At his father's urging, Tarnis refused the Knight's request that he surrender and drew his red-bladed lightsaber. The Sith Lord attacked the two Jedi, dueling them before the holoterminal in clear view of Angral and the others. Unleashing a blast of violet lightning, Tarnis also attempted to choke one of the Jedi, but the other was able to break the Sith's concentration by engaging Tarnis with their lightsaber. However, despite Tarnis's training by his master Lord Praven—one of Darth Angral's apprentices and the Pureblood Sith who was watching the fight—and the strength in the dark side he inherited from his father, the Sith Lord was no match for the Knight and Carsen together. Angral was forced to watch as the Knight struck down his son before his very eyes, driving the Sith into a furious rage. Angral declared an undying hatred for the Knight, warning the Jedi that the Sith would receive retribution no matter how many had to die in the process. His companions promised to avenge Tarnis in an attempt to please their master, and warned the Knight that they already controlled the Republic's weapon facilities. With a final warning for the Knight to take to the Council, Angral abruptly ended the conversation.

Fortunately for Coruscant, the Planet Prison had not yet completed its startup sequence, and the two Jedi were able to disable the device and destroy it. But upon returning to the Senate Tower and speaking with General Var Suthra, the Mon Calamari who had started the Planet Prison project, the two Jedi realized something terrible. Earlier, one of the analysts from the Strategic Information Service, the Republic's primary intelligence agency, had decrypted datafiles recovered by the Knight and T7-O1 from Tarnis's agents previously. In doing so, she discovered that the files contained information on all of the Republic's weapon projects. The SIS had traced a transmission from Tarnis to Angral before the former's death containing the project files, and Var Suthra feared the Sith Lord was already making his move. Declaring war on the Jedi in transmissions across all Republic channels, Angral began to seize control of the Republic weapons projects. While the Empire officially disowned Angral and stated that he was no longer acting with their interests, many in the Republic doubted their sincerity.

Suthra asked the Jedi to go to Ord Mantell, where his agents had traced the signal to a secret listening post The Knight also took Kira Carsen on as an official Padawan, assuming the role of Carsen's teacher at the behest of Grand Master Satele Shan. From there, the two Jedi and T7-O1 would travel across the galaxy in an attempt to destroy the superweapon projects now under Sith control. The conflict with Angral would only end after the Sith Lord used the Desolator superweapon—a combination of the stolen Republic weapons technologies—to devastate the agriworld of Uphrades. Having successfully tested the weapon, which he had integrated into his personal flagship Oppressor, Angral headed to the Jedi Order's homeworld of Tython intending to destroy it as well. The Knight and Carsen intercepted Angral's ship above Tython and disabled the Desolator before facing their enemy in a duel aboard the warship's bridge—a duel that ended with Angral's death and the destruction of the Oppressor.

The duel in the Jedi Temple ruins was created for Star Wars: The Old Republic, a massively multiplayer online role-playing game released by BioWare and LucasArts on December 20, 2011. It appears in the Jedi Knight class story mission "Race to the Ruins", the finale of the Jedi Knight's storyline on Coruscant and the Jedi Knight class' Prologue. After the player discovers that Tarnis has taken the Planet Prison to the Jedi Temple, the player must make their way through The Works, a map accessible by an elevator in the Justicars' Sector map. As the Jedi Temple taxi pad is only accessible once the player has unlocked the taxi pad at the end of The Works, the player must make their way through The Works to the taxi pad at the far end of the map. Throughout the area, the player must fight rogue droids, which are expanded on in the general mission "Meltdown!", and later Imperial soldiers in the second half of The Works and the Jedi Temple map itself. The Imperials' presence is explained in the Heroic mission "Enemies of the Republic", where the players must recover a navicomputer from the ruins of the Temple, for which the Imperials are also searching.

The mission itself features only one alignment-based choice; namely, whether to ask Tarnis to surrender or not. Asking for Tarnis's surrender gains the player fifty light side points, but the other options do not result in any alignment points. Regardless of the player's choice, Tarnis will still fall in the duel, and events proceed as they do above. The mission itself introduces many of the main characters for the class' Act I storyline, and serves as the main event that drives the plot of the next Act. Tarnis's death causes Darth Angral to declare war upon the Republic, and Act I consists of the player attempting to find and destroy the Republic superweapon projects—or, in the case of Taris, the former Republic scientist Nasan Godera—which have been captured by Angral's three apprentices: Sadic, Praven, and Nefarid. The player also receives their personal ship at the end of this mission, as Suthra sends them to Ord Mantell to investigate a Sith base. The duel is briefly mentioned in the 2012 reference guide Star Wars: The Old Republic Encyclopedia, in the summary of the Jedi Knight class storyline.

• Star Wars: The Old Republic Encyclopedia