Background
Kethai Vera was once a speeder mechanic on Mygeeto. She grew up during the Clone Wars, seeing the chaos and violence it wrought firsthand. She was quite glad when the Empire took over, thinking they would act as a stabilizing force.
In the waning months of the clone wars, Kethai had a fling with a Republic naval officer, and unfortunately ended up pregnant from it, though she did get a nice stipend from the Republic to keep quiet about it. She used what meager earnings she got from her technical skill to repair speeders and the occasional starship, kept her head down, even helped out the Empire for free in thanks for them stopping the war and keeping things stable.
Unfortunately, her son, Camron, was far more critical of the empire. He was always a compassionate sort and didn't take kindly to the cruelties of the empire that Kethai was willing to tolerate for security. One day, she returned home and found her son was missing. When The Empire refused to help find him, she realized what had happened, and a month later she was at yavin, working to help the rebellion.
Motivation
Stop anyone else from suffering what she did, and redeem herself for her initial apathy at the suffering of the galaxy.