Rinzler, formerly known as Tron, is Clu's primary enforcer and the secondary antagonist in Tron: Legacy. He is an exceptionally manipulative, traitorous, and skilled warrior and is the elite combatant in all games in the Grid. In addition, he is the only known program to use two identity discs in battle.
Originally known as Tron, Rinzler's identity came into being when Tron was supposedly "killed" by Clu 2.
Rinzler first appeared as the final opponent of the Disc Wars, where he identified Sam as a user after seeing him bleed, and brought him before Clu. He was later summoned when Quorra interrupted the Light Cycle duel, but was unable to prevent her from rescuing Sam.
Despite the setback, he continued to assist Clu 2, acting as a personal enforcer.
On Clu's Carrier Ship, Kevin, Sam, and Quorra noticed Rinzler patrolling the area, and Kevin immediately recognized him as Tron, the former System Monitor program of the Tron system. Quorra allowed herself to be captured by Rinzler in order to lead him away from Kevin and Sam. Rinzler took her to Clu for interrogation, before being charged with escorting her back to Clu's Command Ship. Once there, Rinzler interrupted Sam who had been in the process of liberating his father's identity disc. He pushed Quorra away to engage Sam in a disc fight, but this battle was cut short when he evaded two thrown discs only to be kicked off a nearby ledge by Quorra, lying forgotten at his feet. Rinzler was left dangling only briefly and promptly vaulted back into the ship as Sam and Quorra made their escape. Clu then arrived with four Black Guards in tow, and together with Rinzler set out in pursuit of the fugitives, following their captured Light Jet with the smaller Light Jets of their own. In the ensuing fight, Rinzler and Kevin Flynn made eye contact. From that point on, Rinzler began to experience flashbacks of when he had once saved Kevin, and was able to overcome Clu's reprogramming, eventually overriding it altogether. Once freed of Clu's control, he deliberately crashed his Light Jet into Clu's, derezzing both craft and allowing the three heroes a chance to escape. Clu and Rinzler scuffled briefly as they fell, but Clu grappled Rinzler's spare baton away, created a new Light Jet for himself, and left Rinzler to plummet into the Sea of Simulation below. Rinzler's circuitry flickered and died after he plunged into the sea. Then it relit in Tron's earlier white glow as he sank out of view.
Rinzler returns in Kingdom Hearts 3D: Dream Drop Distance as an antagonist (and on Sora's side, a boss) in The Grid. He is the original copy of the Tron Sora met in Kingdom Hearts II, albeit under CLU's control.
Sora first encounters Rinzler on a bridge while on the run from CLU's guards. The two face off, but before they can do battle, Rinzler is contacted and escapes. Sora, confused, then meets the Flynns and Quorra, who explain Rinzler's true identity and their predicament. The four then decide to split up, with the Flynns searching for the portal back to their home while Sora and Quorra infiltrate the Rectifier to find Tron's source code.
Meanwhile, Rinzler returns to CLU and shows him footage Sora and the Keyblade.
Upon arriving at the Rectifier, Sora and Quorra try to find Tron's source code, but they are unable to accomplish their goal. Just then, Rinzler arrives. Sora tries to jog Rinzler's memory, but Rinzler shakes off Sora's attempts and attacks them both. Quorra then tries to fend off Rinzler, but she is quickly overpowered and seemingly derezzed.
Later, after a conversation with Young Xehanort and Xemnas, Sora is sent to the Disk Wars and pitted against Rinzler. CLU appears to Sora and makes an ultimatum: If Sora hands over his Keyblade, CLU will restore Tron back to normal. When Sora refuses, CLU sics Rinzler on Sora to "take [the Keyblade] by force." Sora is unwilling to fight the original copy of his friend, but Quorra encourages him to fight, revealing that Sora was able to make it through Rinzler.
Eventually, Sora is able to defeat Rinzler and restore Tron's memory. An enraged CLU arrives and promptly hurls his Identity Disk to kill the Keyblade wielder. Tron is able to deflect the disk, but it instead breaks the floor he was standing on. As he falls, Tron reaches for Sora's hand, but Sora is unable to save Tron. His ultimate fate is unknown, but since CLU mentions having to retrieve Rinzler, he may very well be alive.
When Riku, the Flynns, and Quorra board the Rectifier, Rinzler ambushes them and captures Quorra. Later, Riku and Sam reach CLU's throne room and confront Rinzler, but Riku knocks Rinzler off the ship.