Watcher X, previously designated Watcher Five and before that, Minder Eight, functioned as a Human male operative within Imperial Intelligence serving the Sith Empire.
Born in the year 3685 BBY, Watcher X underwent genetic modifications while in utero as part of a collaborative project between the Imperial Science Bureau and Imperial Intelligence. At the age of 21, in 3664 BBY, he enlisted with Intelligence and demonstrated exceptional performance. However, the events of Operation: Undertow prompted a reassessment of his suitability for service. He developed a tendency to perceive nonexistent connections and conspiracies, leading to his forced retirement. Deemed too dangerous to eliminate but too valuable to utilize, he was confined to a section of Shadow Town located on Nar Shaddaa.
Around 3643 BBY, Cipher Nine encountered him, and he assisted the agent in dismantling the local cell of the Eagle's network. Watcher X informed Nine about the terror cell's use of Cyclone, a hazardous stimulant. He provided the location of a Cyclone vendor in the Corellian Sector and a serum to disguise the agent as a Cyclone addict, enabling them to trace the drug's origin. Despite Nine's failure to acquire Cyclone from the two Nautolan dealers, the agent successfully obtained a blood sample from a deceased Evocii.
Following Watcher X's instructions, Nine proceeded to an abandoned medical facility in the Duros Sector to analyze the sample. The data was then transmitted to X, who determined that the technology required to produce Cyclone belonged to Synchet Industries, which had declared bankruptcy five years prior. He identified a former Synchet executive, Jordel Tlan, who had departed the company before its official dissolution and was residing at the Star Cluster Casino. Watcher X suggested poisoning his drink and offering the antidote in exchange for his information. Watcher X infiltrated Tlan's security systems and overheard Nine extracting the information, discovering that Tlan had sold off a medical subsidiary, VerveGen Corporation, to unknown buyers, whom he suspected were the terrorists. Subsequently, Watcher X directed Nine to hack terminals around VerveGen headquarters before recalling the agent to Shadow Town. There, X provided Cipher Nine with a series of implants to create a holographic disguise as a droid, enabling infiltration of VerveGen, albeit under Kaliyo's supervision.
After Nine successfully infiltrated the building and eliminated the terror cell leaders, Watcher X noticed a cyborg survivor and instructed Nine to uplink his cybernetics, allowing him to pinpoint the communication hub and prevent the remaining cell members from regrouping. However, while the agent was carrying out this task, Watcher X exploited the hub's disruption, knowing it would destabilize Shadow Town, facilitating his escape. Nevertheless, X couldn't resist informing Cipher Nine of his actions. Aware that Imperial Intelligence would pursue him, he offered information about Intelligence and Kaliyo Djannis' true history in exchange for Nine covering up his escape. Nine agreed.
Without Nine's knowledge, the implants Watcher X had installed allowed X to manifest within the agent's mind. In 3642 BBY, when Nine was dispatched to infiltrate Ardun Kothe's SIS team, the spymaster employed the agent's own brainwashing code to compel the agent to obey his commands. During this time, X voiced his observations, with Nine remaining unaware of the mysterious voice within their head. After completing a mission for Kothe on Taris, Watcher X revealed his presence to Nine and explained that this type of brainwashing was an Imperial tactic, not a Republic one, indicating that Imperial Intelligence had betrayed Nine and provided their information to the Republic. Secretly accessing the archives in Imperial Intelligence HQ back on Dromund Kaas, Nine confirmed that the brainwashing had indeed been ordered by Intelligence. Searching through the records, Nine discovered the IX serum that had been used to condition them could be used again to reset and then shut down the conditioning. The chemicals required for it could be found on the poisonous world of Quesh, and Nine was able to secure a ready supply of the required chemical, dimalium-6. However, the serum would take time to make and circulate through the Agent's system.
After Nine recovered the shuttle Starbreeze on Hoth, the agent returned to Quesh at Kothe's order, and discovered that he had preparing to secure the Shadow Arsenal as deterrent to prevent further war. As Nine is ordered to remain at the Arsenal facility shield controls, Adrun Kothe determines that Nine's usefulness had reached its end. While the IX serum hadn't fully circulated through Nine's system, Watcher X determined that it was enough to reset the conditioning, at the risk of being put in a permanent vegetative state. As the conditioning reset itself, X gave Nine final orders to stop the SIS and find out how they obtained Imperial brainwashing codes. Before disappearing, Watcher X told Nine that there were truths that must be uncovered.