Background
IG-81X was the tenth in a line experimental modals of the IG-81 series. IG-81X was designed as an assassin droid with additional loyalty protocols, intended to make IG-81X more effective in collective combat situation.
Initially deployed to the Empire, IG-81X worked with the ISB on a number of classified missions. IG-81X was responsible for a number of high profile assassinations in the very early days of the Empire. Many of these were under the command of Admiral Vinar Corlan's secretive Exaction Unit.
IG-81X was a highly successful assassin droid, much sought after for critical Imperial missions. And all seemed to be going well until he was called to Coruscant by Moff Dardano.
Dardano, more of a polititian than militaryu commander, instructed IG-81X to assassinate Admiral Corlan. At this point, Daradno's instructions conflicted with IG-81X's loyalty protocol. IG-81X informed Dardano that he would be unable to undertake the mission.
At this point, Dardano flew into a rage. His guards siezed and disabled IG-81X. When IG-81X was reenabled, a restraining bolt had been installed and additional janitorial programming have been integrated into IG-81X's original instruction set.
Unable to override the programming because of the restraining bolt, IG-81X waited for the right moment, which arrived with a Rebellion raid of Whisper Base. Freed from the restraining bolt an the onerous janitorial programming, IG-81X joined the Rebellion and vowed revenge against Dardano and the Empire as a whole.
Motivation
Quest - Vengenance - The Empire put a restraining bolt on IG-81X and turned them into a janitor droid. IG-81X is not happy about this.