Background
The droid, designation F83DJD9BHLMTYCSZD7B7ATWY9C, was no stand-out amongst the other F8-series repair droids aboard the Admonitor. Since it's assembly and deployment into the service of the Empire it performed its duties with the speed and skill expected of the tried and true model of technician. As time drew on newer techs would begin phasing out the old gaurd - F8s being replaced with G1s and F9s or the fleshy equivalents of mechanics. F8-3D's decommissioning was destined to happen at some point from the moment he left the assembly line. At best he could hope to be given a position on a starbase or some distant outpost, at worse he would be auctioned off for scrap or sold into servitude as meager fuel for the Empire's insatiable need for resources. The latter, unfortunately, proved to be the case - but it would not be the last time F8-3D would be of service to the Imperial Regime.
Many methods of discovering, dissuading, and eventually destroying dissent against the Empire were proposed in its infancy. While assassination droid were useful and sometimes quite effective at eliminating high profile targets, there were situations where even they would bring undue attention to themselves and jeopardize the mission at large. An engineer named Myri Pellaeon devised a series of subroutines that could turn even the most inconspicuous MSE-6 into a potent killing machine. The injected code would cause periodic corrosion of normal repair processes resulting in mistakes that could prove fatal, either immediately or over time. F8-3D was one of many service and astromechs droids chosen to be the subject of unsanctioned testing when her formal proposal was not given the attention she believed it deserved.
Sold to a bothan bounty hunter named Pol Sei'Tre whom Jr. Lt. Pellaeon had some personal squabbles with, F8-3D proved to be worth every credit spent for the first eight months of his service aboard his ship. Unfortunately, while passing through an asteroid belt just a few clicks from making a delivery to the Siska Colony, the ship suffered an engine malfunction that sent it careening into a chunk of space rock.
Months later the wreckage was picked up by Terrelian's passing through, among the salvageable metal was a functioning tech droid. It was taken with them and employed to repair a stock of droids that they had purchased, being functional for several months before their life support systems suffered a cataclysmic malfunction as a result of their faulty food dispensing system being wired into the oxygen controls. The lifeless remains of the ship - corpses and all - were towed to a nearby planet where F8-3D passed from owner to owner for years, some meeting untimely demises and others simply growing suspicious of this cursed droid.
Motivation
Ambition { Friendship: Lives a lonely existence because his owners have a bad way of meeting untimely demises;
Cause { Support the Empire: Had an assassination sub-routine installed when he was decommissioned and sold off;
}