Unit 26, alternatively designated as Unit 2-6, was a BX-series droid commando. This particular droid took part in the seizure of Rishi Station during the Clone Wars, operating alongside fellow commando droids such as Unit 07.
Back in 22 BBY, Unit 26, together with other Separatist BX-series droid commandos, received orders to infiltrate Rishi Station, a Galactic Republic outpost located on the Rishi Moon. Their mission was to activate the "all-clear" signal, thereby paving the way for a surprise assault on Kamino, a crucial Republic planet. Unit 26 and its droid comrades utilized Droch-class boarding ships, leveraging a meteor shower as cover to approach and land near the station. After gaining entry through stealth and eliminating several clone troopers, the droids successfully hard-wired the "all-clear" signal, even though some clones managed to escape.
When Clone Captain CT-7567, known as "Rex," and Clone Commander CC-2224, known as "Cody," arrived for a routine check, Unit 26 attempted to deceive them by disguising itself as a clone, approaching them in an attempt to stop the inspection. However, when Rex and Cody were alerted by a droid attack flare, Rex fired upon and destroyed Unit 26, who was in disguise. Although Cody was surprised, Rex swiftly put him at ease by removing the clone helmet, revealing Unit 26's faceplate. At that time, they were ambushed and forced off the platform, leading the Separatist droids to believe they had been eliminated. Subsequently, Unit 07, 08, and 09 were assigned to guard the base entrance. Rex then tricked Unit 07 into opening the doors, claiming to be Unit 26. As the doors opened, Unit 07 and the other droids were destroyed, enabling the clones to successfully retake the base. However, a fleet of Separatist warships soon arrived, deploying reinforcements to recapture the station.
The initial appearance of Unit 26 occurred in "Rookies," an episode from 2008 belonging to the first season of the TV show Star Wars: The Clone Wars.