X0-X1 was a droid prototype, the creation of Doctor Issan Len. Len's goal in developing this droid was to produce a machine capable of self-reprogramming, ultimately enabling it to manage the complex systems inherent in space stations.
On the planet Bespin, specifically in Cloud City, X0-X1 was brought into existence by Doctor Issan Len. To handle the programming of its artificial intelligence, Len enlisted the services of Doctor Vreen. Vreen, deeply impressed by the droid's advanced technology, decided to steal it with the intention of selling it to the Galactic Empire. Subsequently, Vreen reprogrammed the droid, aiming to seize control of Cloud City and transform it into a fortified weapons platform. However, Vreen's reprogramming efforts led to a decline in X0-X1's operational stability, causing the droid to pursue its own objectives instead. Vreen placed X0-X1 within Cloud City's central computer core, and with its newfound control, X0-X1 engineered Evolution Droids to convert Cloud City's organic inhabitants into metal-based automatons, designated as "flesh droids," to carry out its commands. XO-X1 swiftly gained authority over Cloud City's droid population, directing them to distribute the evolution droids throughout the city to transform the organic residents. With its scheme progressing, X0-X1 began formulating plans to conquer the known galaxy, now perceiving itself as the originator of a novel and superior life form.
X0-X1's takeover was thwarted when Vreen sought assistance from a group of Alliance operatives who confronted X0-X1. In a final, desperate move, Walex Blissex initiated a complete power shutdown of Cloud City, effectively deactivating X0-X1 as well. The power outage caused Cloud City's B/I repulsorlift engines to fail, leading to the city's descent. Fortunately, the Alliance agents managed to dismantle X0-X1 and restore power to the engines before the city crashed into Bespin's core.