Background
Former Clone Trooper that discovered that the chip is meant to execute Order 66 not to enhance combat skills. Alongside with Cap. Rex and Comm. Cody he disobeyed the Order and stand aside the Jedi. For that he and other clones that remain independent is being hunted by the Empire. Bred to be superior to battle droids, gain excessive combat skills and piloting skills. Since the "betrayal" he fled to the Outer Rim and worked as a hired gun hoping that the Empire will not be notified bout his presence.
Motivation
Overthrow the Empire: The character despises the Empire and everything that it stands for. He may or may not be an active member of the Rebellion, but he supports its goals and gives aid and comfort to those against Imperial tyranny.
Keeping low presence at all costs. Anytime someone will recognized former clone trooper in him, became a major threat and must be eliminated or blackmailed. Will be recognized by every former Clone Trooper, a Jedi or a Sith on sight. Also he sworn an ought to free and protect every other clone trooper that is trying to run from the Empire.