Background
Klugoa Sepus was born in the year of 33BBY. His parents were very politically invloved and fiercely loyal to the republic. As a child he was very adventurous and loved to go exploring which got him into a lot of trouble.
This love of adventure led Klugoa to become an archeologist/treasure hunter. One day when he was on a distant planet looking for an elusive treasure, he got word that the black sun had completely slaughtered his whole village along with his wife and children. It was that day he swore an oath to avenge their deaths.
He later found out that the Black Sun was hired by the Empire to wipe out his village because there was Zabrak rebellion base. Klugoa already hated the empire so this all-the-more fuels his hatred of the Empire.
Motivation
Take out the black sun. Klugoa is consumed by his the sadness of his family's death and his rage towards the organization that caused it.