In his original identity of Tron, Rinzler was a computer program and ally of Kevin Flynn, having been created by Flynn's friend and business partner Alan Bradley. Tron worked together with Flynn to liberate ENCOM's computer system from an evil artificial intelligence known as the Master Control Program, or MCP. Later, Flynn brought Tron into a system he himself had created to serve as it's protector along with Clu, Flynn's virtual clone. However, after the emergence of the ISOs, or isomorphic algorithms, Clu rebelled against his creator and attempted to eliminate Flynn. Tron defended his friend and obtained a second identity disk in the process, but was thought to have been destroyed by Clu in his effort to enable Flynn's escape.
In reality, Tron was "repurposed" into Clu's loyal enforcer and given the name Rinzler, as well as a suit of armor that obscured his former identity. He retained some sense of self, and was able to recognize Kevin Flynn's son Sam as a User, or human, when Sam was injured in combat with him on the Grid. Rinzler was later employed by Clu in his efforts to hunt down the Flynns and their ally Quorra, the last known surviving ISO. However, the chase rekindled Tron's buried memories and he turned against Clu, only to be thrown into a virtual sea during their confrontation. As he sank, his armor highlights flicked from orange to his previous white color.