Background
His village was captured by imperial storm troopers while he and his friend were off foraging. He and his best friend had a chance encounter with a rebel team looking for an imperial slave compound and joined with them. They were trained and a month later when the complex was found, they joined the assault. The assault was costly but successful, His friend left on his own when they found that some of their village was still missing and he stayed with the alliance.
Motivation
Cause: Overthrow the empire: There is no real question as to what his feelings are towards the empire. As far as he is concerned they are no better than slavers.