The Desolator was a superweapon built by the reconstituted Sith Empire during the Cold War with the Galactic Republic. Combining the technologies of the Planet Prison, Shock Drum, and Death Mark laser—all weapons projects stolen from the Republic superweapon initiative—the Desolator was a ship-mounted weapon designed as a planet killer. Built by the Sith Lord Darth Angral during the Desolator crisis, the weapon was the central part of his plan to exact revenge upon the Jedi Knight who had killed his son Tarnis. The Desolator's first and only successful test of its capabilities was on the agriworld of Uphrades, but the destruction of Angral's warship Oppressor above the Jedi homeworld of Tython brought the weapon's short-lived reign of terror to an end. The technology would later be salvaged by Imperial engineers, giving rise to the far less powerful Firestorm Turbolaser.
A combination of three separate superweapon technologies, the Desolator was designed to be mounted directly onto a starship and integrated into the ship's systems. The first stage of the weapon, developed from the Planet Prison weapon, ionized a planet's atmosphere and effectively transformed the world into an enormous ion cannon. This prevented any craft from landing or taking off as well as disrupted communications, trapping the inhabitants of the target planet. The second stage, building off of the Death Mark laser, ignited the planet's ionized atmopshere and turn the very air of the target into a firestorm. The laser would also penetrate the planet's crust, allowing the third and final stage to proceed. Using technology developed from the Shock Drum weapon, the Desolator would then destabilize the target world's core with a sustained series of intense seismic vibrations. These vibrations would cause the planet to literally tear itself apart in a matter of hours, with large chunks of the world breaking off and smaller debris creating an asteroid field surrounding what was left of the planet. The firestorm in the atmosphere would eventually die down in a matter of hours, though the ionization was expected to take several months to dissipate, preventing any rescue attempts. The Desolator inherited the major flaw of its predecessor, the Planet Prison, in that it required both a massive amount of energy to fire and extended periods of time to recharge. The Sith Lord Darth Angral, who developed the Desolator, mounted it on his warship the Oppressor and devoted three of the ship's reactors to powering the weapon.
The Desolator weapon was developed from several different weapons projects, all of which were created by the Republic superweapon initiative—a weapons program started by the Mon Calamari general Var Suthra during the Cold War between the Galactic Republic and the Sith Empire. However, Tarnis—the son of the Sith Lord Darth Angral and a Sith Lord in his own right—decided to infiltrate the Planet Prison project on the Republic capital of Coruscant by posing as a Republic scientist. Masking his status as a Sith Lord through the Force, Tarnis operated under the name "Eli Tarnis" for several years as the project neared completion. He also had a hand in the other projects, and unbeknownst to his fellow scientists, the Sith designed a way to combine the different technologies into a single device, which he gave the codename "Desolator". In 3643 BBY, the research team completed the prototype of the Planet Prison and were preparing to start field tests when Tarnis's presence was detected by the Jedi Order—though the Jedi were unaware as to the precise source of the disturbance in the Force they sensed.
Feeling that his position was threatened, Tarnis hired the Migrant Merchants' Guild and Black Sun criminal organizations to steal the plans for the device and to stage his kidnapping, and the Sith masterminded an elaborate ruse upon the Republic so that he could escape to the ruins of the Jedi Temple to set up the prototype. However, Tarnis was pursued by a Jedi Knight, the former apprentice of Jedi Master Orgus Din, and the Padawan Kira Carsen. The two Jedi fought and killed Tarnis before a live holofeed of Darth Angral and his three apprentices, and Angral declared undying hatred for the Jedi Knight who killed his son. Angral then waged war upon the Republic in a quest for revenge, using the files on the superweapon initiative that Tarnis had sent him before his death.
By using files on the Republic's superweapon projects—sent to him by his son before Tarnis's death—to seize control of the Power Guard Project, the Shock Drum, and the Death Mark laser weapon. Sending his apprentices Sadic, Praven, and Nefarid to Nar Shaddaa, Tatooine, and Alderaan respectively to take control of the projects, Angral also pursued rumors of Doctor Nasan Godera's presence on Taris by sending Imperial Intelligence to capture the scientist. Using information gathered by his apprentices on the captured weapon projects, Angral had his scientists begin combining the different technologies.
Although the Desolator superweapon was destroyed in orbit above Tython, the legacy of Darth Angral and his son Tarnis lives on. Imperial scientists have adapted the Desolator technology into a new form: the Firestorm Turbolaser. These cannons superheat the atmosphere in a targeted area, literally setting the air on fire and incinerating anyone unfortunate enough to be caught within the area of effect.
The Desolator first appears in the massively multiplayer online role-playing game Star Wars: The Old Republic, released by BioWare and LucasArts on December 20, 2011. The central plot device of the Act I storyline for the Jedi Knight class, it is first mentioned in "New Intelligence", the first mission of Act I on the Republic-only planet of Ord Mantell. The player's companion T7-O1 recovers a series of transmissions and files from one of Darth Angral's bases in a raid on the facility, and T7 mentions that the files contain references to something called the "Desolator."
It is not explicitly mentioned until much later in Act I, after the player has completed the class storylines on Taris, Nar Shaddaa, Tatooine, and Alderaan. The player then travels to the class-restricted location of Uphrades, which has been destroyed by Angral with the Desolator. After defending the Republic medical frigate Daybreaker from an Imperial attack, the player follows Angral to Tython and boards his warship, the Oppressor. While T7 remains behind, the Knight and Kira Carsen disable three reactors in order to take the Desolator offline, and then face Darth Angral on the ship's bridge. After successfully defeating Darth Angral and the possessed Carsen, the player and Carsen escape from the Oppressor moments before Republic bombers destroy the ship and the Desolator with it.
The Desolator receives a mention later on in Act III of the Jedi Knight story, during the mission "Firestorm" on Corellia. In a Codex entry gained during the mission, it is revealed that Imperial engineers adapted the atmospheric effects of the Desolator technology into the Firestorm Turbolaser.