Sark is a command program introduced in Kingdom Hearts, and originally taken from the Disney film Tron. He is a loyal enforcer to the Master Control Program, and sees no need for users. This puts him in conflict with Tron's goals of keeping the system running in service of users.
Kingdom Hearts II
By this time, Sark and his army of digital Heartless have conquered Hollow Bastion OS for the MCP. Upon the MCP arresting three Users abusing the keyboard, Sark is sent to capture them after they are sucked into Space Paranoids. While a squad of Strafer collect Donald and Goofy, Sark appears before Sora and intimidates him into complying by attempting to de-rezz Donald and Goofy.
Meeting the MCP, Sark questions why they keep Tron around, as they do not have enough processing power to use a logic probe to search his code for for information on the DTD. They are alerted to Sora's group breaking out of the Pit Cell.
Sark appears again at the MCP's hub when the heroes arrive to erase it to save the town, where he and a squad of Heartless stand in wait. Defeated, Sark comments he could have made a great team with Tron, who knocks him out. The MCP empowers Sark with his own functions, causing him to grow in size. When the MCP is deleted, Sark fades away with him, due to sharing his functions.
Sark, like Tron, resembles a grey-skinned human male under his grey armor. Like Tron's, his armor is covered with circuity, but his circuitry is red with an orange glow. The circuitry on Sark is also much more complex than Tron's and sports a "V"-shaped symbol in several places. Sark's helmet is attached to his armor and covers every part of his head except his face. His Identity Disk is attached to his upper back.
Sark is arrogant and ruthless, seeking to derezz Tron for disobeying the MCP. He is loyal to the MCP and his vision of Space Paranoids, in which the system is independent of users.
Sark originated from the 1982 movie Tron, portrayed by British actor David Warner. He was the Commander of the MCP's army and overseer of the Game Grid. When Tron, his user Flynn, and another program, Ram, escaped the Game Grid, Sark was ordered to round them up. After a battle between Tron and himself, Tron's Identity Disk cut through Sark's head. The MCP restored him, giving him all his functions to stop Tron. When Flynn defeated the MCP, Sark was derezzed along with him.
As David Warner was unavailable to reprise his role as Sark and the MCP due to a previous commitment, both were voiced by Corey Burton.