Milky was a Nimbanel criminal who served the Republic in the Clone Wars in order to reduce his sentence. He fought alongside Miles O'Keeffe to liberate the planet Salvador from CIS control, among other battles. Miles was constantly pulling Choad out of scrapes, but the Nimbanel always helps O'Keeffe remember to smile through tough times as well.
After he was released from his prison term, Milky went back to work for the Kheedar Ring, the criminal organization that got him sent to prison in the first place. His debt to the Ring got out of hand, and he began feeding information to the Empire about the Ring's activities. He had turned rat, and when the Kheedar Ring began to suspect it, Choad split. He tracked down his old war buddy Miles on the planet Libertash, and begged him for help. Miles had settled down and no longer wanted to be mixed up in those things. He sadly turned Milky away. The Ring murdered him shortly after and left his body in Miles' office.
Miles realized he had betrayed a friend in desperate need, and hunted down all five heads of the Kheedar Ring one by one and cashed their checks.