Lock was a clone trooper who achieved the rank of Clone Captain within the Grand Army of the Galactic Republic during the era of the Clone Wars. Under the command of Jedi General Eeth Koth, this Clone Captain led the clone trooper unit belonging to the Jedi Master around 21 BBY. During that year, Lock found himself stationed on the Venator-class Star Destroyer Steadfast, Koth's flagship. While serving aboard the Star Destroyer, after the Republic's recapture of the planet Geonosis, Lock joined the Jedi Master in his pursuit to uncover the individual responsible for the mysterious attacks plaguing Outer Rim Territories hyperspace routes, a journey that took them through the Saleucami system.
However, as the Steadfast traversed the Saleucami system, it was ambushed by a fleet belonging to the Confederacy of Independent Systems, led by General Grievous. In the ensuing chaos, Lock and his fellow clone troopers found themselves battling Separatist battle droids that had boarded the Star Destroyer. Despite the ongoing battle, Koth instructed the Clone Captain and his troopers to abandon the Steadfast, leaving the Separatist general to him, a decision the clone trooper contested. Regardless of his orders, Koth was swiftly defeated by Grievous in a brief duel that took place on the command bridge.
The clone known as Lock was a clone created from the genetic template of Jango Fett, a human male bounty hunter. Born and raised on the planet [Kamino](/article/kamino], he was destined to serve within the ranks of the Grand Army of the Republic during the Clone Wars, a widespread conflict that engulfed the Galactic Republic and the Confederacy of Independent Systems. Achieving the rank of Clone Captain, he was assigned to a unit under the command of Jedi General Eeth Koth, who was also a member of the council-member. In 21 BBY, Lock found himself stationed on the Venator-class Star Destroyer Steadfast, in company with Eeth Koth and the rest of his unit. While the Steadfast was within the Saleucami system, the ship came under attack from a Separatist fleet. This fleet was led by Supreme Commander General Grievous aboard his Recusant-class Commerce Guild destroyer, and Separatist forces boarded the Steadfast using docking tubes.
The subsequent battle forced Lock and his clone troopers to defend the airlocks of the ship against the incoming waves of B2-series super battle droids. Koth reached out to Lock, requesting an immediate update on the situation, to which the captain responded that the sheer number of droids was insurmountable. Koth then issued an order for Lock and his troops to evacuate the vessel using escape pods, declaring that he would personally confront Grievous on the bridge. Lock protested, emphasizing that the droid general's forces included BX-series droid commandos, but Koth dismissed their significance and reiterated his order to evacuate. Shortly thereafter, Koth and his troops were confronted by Grievous and a squad of commando droids on the bridge. The Jedi engaged Grievous in a desperate lightsaber duel, but Grievous ordered his droid escort to assist, leading to Koth's ultimate defeat and capture.
Mirroring the clones derived from the bounty hunter Jango Fett, Lock possessed a height of 1.83 meters. During the ambush on the Steadfast, the Clone Captain demonstrated an understanding of the overwhelming force that outnumbered his clone trooper unit when asked for a status report on the engagement. When the Jedi Master instructed Lock and his troopers to retreat, the clone trooper voiced his reservations regarding the Jedi General's decision to confront Grievous.
Lock was outfitted with Phase I clone trooper armor, adorned with the green and yellow markings that signified his affiliation with Eeth Koth's unit. In addition, his helmet featured a visor, and an antenna was affixed to his left shoulder plate. In combat scenarios, Lock wielded a DC-15A blaster carbine, a standard-issue weapon provided to clone troopers of the Galactic Republic.
Lock's initial appearance was as an unnamed character in "Grievous Intrigue," the ninth episode of the canon animated series Star Wars: The Clone Wars' second season. This episode aired on January 1, 2010, and featured the voice acting of Dee Bradley Baker. Lock was identified by name in the episode's accompanying guide, which was released on StarWars.com.