Dawn of Defiance
Sartok was the leader of the rebel Nazren in the Bespin Orbit.
A year ago, in the Bespin system, Sartok took commandeered the slave ship that imprisoned his people, as the heroes came to his aid in a fierce orbital battle. They managed to disrupt the slave circuit that controlled his ship. Many Nazren on that ship died in the fight to capture it and he escaped shortly before a Star Destroyer arrived.
Sartok camped at a remote settlement for several months to train his men and to disembark the weak and infirm. In a bold move, he brought the ship back to Nizon, where it was attacked by the Imperials and damaged in the asteroid field. He managed to crash it in the wastes. Many of his rebels survived though, infiltrating The City, where they began to set up a resistance movement.
The resistance was dealt a severe blow when his men attacked an Imperial detention center. The main force was destroyed easily through a combination of patrolling V-Wings and Walkers. The remaining soldiers were captured and a holo was posted throughout the city, depicting Sartok attempting to kill the revered Nazren shaman Krusk. The stormtroopers captured him and his men and saved the shaman.