Watcher One was the designation given to a male Human Intelligence Operative. He operated on behalf of the reconstituted Sith Empire.
During the era known as the Cold War, which involved the Galactic Republic and the Sith Empire, he oversaw an operation conducted on Taris. The operation's objective was the retrieval of Doctor Nasan Godera, a former scientist of the Galactic Republic. Godera was responsible for the creation of numerous Republic superweapons. Within one of Godera's laboratories, Watcher One's forces encountered a Jedi Knight who was also seeking the doctor. Watcher One tried to shake the Jedi's confidence by exposing his knowledge of the Knight's activities on Tython, but the Jedi was not deterred from his mission to find Godera.
After the Jedi Knight successfully overcame an ambush set by the agent's forces, they assisted Godera's droid, known as RE-M0, in repairing the facility's computer systems. This repair allowed them to track Godera's biosignature. By recalibrating the tracking relays, the Jedi was able to trace the Imperials to a base located south of Lake Brell, specifically within the dilapidated remains of an old chemical processing plant. Upon entering the facility, the Jedi encountered a Rodian by the name of Vulaa, whose companion had sustained injuries. The Jedi advised Vulaa to seek cover and ensure the safety of his friend, while they ventured further into the depths of the facility.
Inside the base, the Jedi discovered Doctor Godera deceased at Watcher One's feet. However, RE-M0 appeared and revealed Watcher One's deception. "Watcher One" and his accomplices then faltered and vanished, replaced by an Imperial shadow squad. After the Jedi defeated the ambushers, Watcher One contacted them, revealing that he had been Vulaa, and his "friend" was the unconscious doctor. Watcher One then proposed a deal with the Jedi: he would disclose the location of a certain Sith assassin poised to destroy a Republic colony in exchange for time to interrogate the doctor. The Jedi was compelled to accept, but continued his pursuit of Watcher One after dealing with the assassin.
By the time the Jedi caught up with Watcher One, he had already extracted the necessary information from the doctor and transmitted it to his superior, Darth Angral. Angral was enraged by Watcher One's agreement with his son's killer. Despite Watcher One's intention to honor his agreement by handing Godera over to the Jedi, he was instructed to bring the Jedi to Dromund Kaas so Angral could personally execute them.
Despite the Jedi's plea for the agent's surrender, they engaged in combat. The Jedi emerged victorious over Watcher One but allowed the agent to depart peacefully. Knowing that he could not return to the Empire and would be killed by Darth Angral for failing, the Knight suggested that he start a new life in the Republic; perhaps the agent would find that the Republic was not the enemy he thought they were. Watcher One was surprised at the Jedi's generosity, but gratefully accepted the offer and departed. This also allowed the Imperial to fulfill his original deal to the Knight in handing over Godera, who was brought back to Coruscant.
Watcher One later sent a farewell message to the Jedi, expressing that while he remained puzzled by his sparing, he had not betrayed the Knight's trust. Having adopted a new identity and life as a Republic citizen, his espionage skills had opened doors in the corporate sector, and he was surprised to find his new life as compelling as his old one. He concluded that the message was the final time he would use "Watcher One," expressing gratitude for his second chance before disappearing into his new life.
Watcher One possessed a strong sense of honor and loyalty, demonstrating unwavering commitment to his assigned tasks. He showed a willingness to employ any means necessary to achieve success in his missions, which included making compromises with adversaries and betraying fellow agents of the Empire. He was particularly aware of the dangers of working under "Sith madness", as he termed it, and had actively avoided potentially lethal situations of Sith temper tantrums for the past twenty years.
Watcher One demonstrated proficiency in interrogation techniques and psychological manipulation, evident in his attempts to undermine the Jedi's resolve by confidently revealing his knowledge of the Jedi's exploits on Tython. His sense of honor prevented him from letting himself be arrested, so Watcher One attacked the Jedi in order to force the Knight to kill him.
The character of Watcher One was conceived for the game Star Wars: The Old Republic, a massively multiplayer online role-playing game launched by BioWare on December 20, 2011. He is featured as the primary antagonist within the Jedi Knight's class storyline on the Republic-aligned version of Taris. The Jedi Knight's pursuit of Watcher One across Taris is driven by the search for Doctor Godera. The Imperial agent compels the Jedi Knight to grant him time for interrogating Godera by exposing the whereabouts of a Sith assassin named Rora Seake, who was on the verge of destroying a Republic colony. Upon Watcher One's defeat, players are presented with options: he can be released (light side), apprehended (light side, but results in his suicide), or killed (dark side).
Watcher One is also briefly mentioned in the Agent story.