Commander Jason Lock (played by Harry J. Lennix) is the supreme commander of all military defense forces of the human city Zion. His character appears in The Matrix Reloaded, Enter The Matrix, and The Matrix Revolutions.
Lock was a naturally-born Zion citizen. This differs from redpill inhabitants, particularly his hovercraft crews and their commanders, most of whom are Matrix inhabitants. His unfamiliarity with the Matrix grounds his views to the unadulterated realities of using any and all resources he can command to evade Machine forces and keep Zion's whereabouts a secret. He is one of the few characters in the films who has a given first and last name. He was at odds with not only the Zion Council when managing the defenses, but with some errant ship captains, especially Captain Morpheus of the hovercraft Nebuchadnezzar. He appears to be bureaucratic, taciturn, unimaginative, and uncharismatic; as a result, he is not highly respected by either his subordinates or by the Council.
As of the beginning of Reloaded, Lock was romantically involved with Captain Niobe of the hovercraft Logos, but loses her to Morpheus (who had been her captain and her sexual partner for some years) during Revolutions. The history of Niobe's relation with Morpheus increased tensions between Morpheus and Lock when discussing defense strategy. Morpheus' and the Council's desire to aid the One frustrated Lock, who felt that the limited resources of Zion's defenses would be better used elsewhere.
Even Niobe became intolerant of his autocratic views after Lock convinced the Zion Council to not let the Logos join the defense fleet, claiming that that ship's size and EMP systems are "too weak to make a difference". After the Council asked for two captains to search for the Nebuchadnezzar, only one captain, Soren of the Vigilant, initially volunteered. When Lock stated to the Council that he found it hard to believe "any man" would volunteer for such a daring mission, Niobe volunteered as a reprisal for being patronized.
As the Machines tunneled toward Zion, Lock devised a strategy where the hovercrafts would be scattered in an attempt to use the ship EMP devices in a combined attack to disable most, if not all, of the digging machines and Sentinels all at once. However, Smith/Bane prematurely set off one of the ship's EMPs, disabling many of the ships. The Machines decimated the helpless ships. This left only the ground forces of Zion to withstand the eventual assault.
By the end of the first wave of the Machine attack, Zion would have fallen were it not for the arrival of the hovercraft The Hammer, piloted by Captain Niobe. The Hammer activated their EMP, disabling all Machine forces. Although the Machines' progress was momentarily halted, Lock was displeased that the Hammer's EMP had also knocked out most of Zion's defenses, saying that they had just handed the dock to the machines "on a silver platter".
When the Council asked his advice as the Machines commenced their attack, the only course of action was continuing with his original back-up plan; gathering Zion's citizens in the Temple and making a last stand at the Temple gates. Neo, who successfully arrived in the Machine City, had negotiated with the Machines: he would defeat Agent Smith if the Machines withdrew from Zion.
His name could be a reference to the philosopher John Locke; however, in Enter the Matrix, when Sparks answers a call from Lock, he utters "Jesus, it's Deadbolt himself", in a derogatory reference to locks. Captain Ballard of the Caduceus also used the term "Deadbolt" during the Captains' meeting in The Matrix Reloaded.
In The Matrix Online, Lock plays an important role for new redpills as they gain reputation for Zion. Among the important things, Lock promotes the redpills to Captain so that they can have their own crew. Other than that, Lock praises the Zion-affiliated redpills a job-well done in pre-recorded messages held by Niobe and Ghost as NPCs.
During renewed warfare with the Machines after the collapse of Neo's Truce in The Matrix Online, the human citizens of Zion were relocated to a safer location deeper within the earth, referred to as New Zion. Lock stayed in Old Zion with a skeleton crew of Zion military personnel after the rest of the city was evacuated. Cypherite spies compromised the security of Old Zion before it was completely abandoned, allowing Sentinels to overrun the city. Lock was not among those rescued from the Sentinels’ attack, and remained missing. Given the devastating nature of the attack on Old Zion, chances seemed slim that Lock could have survived. Captain Roland was promoted to succeed Lock as the Commander of Zion's military.
Lock was eventually found alive by E Pluribus Neo operatives when they were salvaging equipment in Zion and was nursed to health in their care. Some months later, Lock was slated for transfer to New Zion aboard Steelle's hovercraft The Hand of God with an escort comprised of three other E Pluribus Neo hovercraft. Data concerning the time and route of his transfer were discovered by Cypherites and they arrived on scene to disrupt the transfer along with Machinists and the special "unibody" hovercraft of a mysterious outsider known as Halborn, who had been tricked into attacking Lock. E Pluribus Neo in turn contacted Zion, who immediately dispatched four hovercraft as reinforcements while interloping Merovingian operatives entered the battle in search of profit. Zion and E Pluribus Neo managed to win the battle, disabling all Cypherite and Machinist hovercraft and negotiating a cease-fire with the Merovingian operatives, thus ensuring Lock's transfer from Steelle's hovercraft to RedBindi's The Titan for transport to New Zion.
Lock currently holds the position of civilian advisor in New Zion, as the Zion council have expressed doubts about his capability and stability following his near-death experience.