Tron

Tron is a party member and the protagonist of Space Paranoids, based on the film with the same title. He is a security program who works to stop the MCP and Sark from destroying Hollow Bastion with their army of digitized Heartless. He becomes good friends with Sora, Donald and Goofy. He appears in Kingdom Hearts II and is considered the most important Disney character in the game behind the primary ones (Donald, Goofy, King Mickey, Maleficent, Pete).

Kingdom Hearts II
Tron meets Sora, Donald and Goofy while trapped in a Pit Cell with them in the mainframe of Ansem the Wise's computer. After escaping the cell and enabling access back to the real world, the four companions proceed to find a way to unlock the DTD (Door to Darkness). After activating a power core, Tron sends Sora and the others back to Hollow Bastion to locate the password required to access the DTD. They locate the password behind a large painting of Xehanort (thanks to Tifa moving it aside), the password being the seven names of the Princesses of Heart. Tron hacks into the DTD and changes the password to Sora, Donald and Goofy, to bide himself time before the MCP attacks again. Sora, Tron and the others reach the I/O Tower where they fight a Hostile Program, which is defeated.

Tron reveals to the three that Ansem is his user (although which Ansem it is remains a mystery). He also explains Ansem rebooted the MCP. During the group's return visit to the mainframe, Tron has been forced onto the Game Grid to fight for his life, while Hollow Bastion is being overrun by digitized Heartless by the corrupted town defense mechanism. Sora and the others save Tron and he learns all the Hollow Bastion residents are supporting him. Tron receives an Eradicator program to delete the MCP. Using the Solar Sailer vehicle to reach the core of the mainframe, Tron, Sora, Donald and Goofy battle an upgraded Sark and the MCP. The MCP is eventually deleted and Sark dies with him. Tron is overjoyed and shows off his "silly side" to his friends, who he hugs in a term of goodbye, before jumping into the core to take over the MCP's programming. He locates old footage of Hollow Bastion when it was first built and revealed its former name: Radiant Garden. Tron is seen in the credits with a new dancing program, that Sora created.

Tron has a unique Limit ability called Setup where he and Sora attack enemies with data. Eventually, Tron gains access to a Reprogram action command which allows Sora to hit a reprogram button, which eliminates all enemies nearby.