Bossk reputation of being ruthless and unflinching was well deserved. After killing his father and leading the Bounty Hunters Guild to notoriety, he was one of several to be hired by Darth Vader to track down the Millennium Falcon. Failing to capture Han Solo, did not stop Bossk from trying to collect the bounty, and was in a collaborative effort to steal Solo from the Slave 1. The group was eventually outsmarted by Boba enroute to Jabba the Hutt palace. Bossk And Boba crossed paths many time mostly in the expanded universe. Bossk is said to have a vendetta against Chewbacca, as Trandoshans hate Wookies.
Trivia: In the first draft of ESB Bossk was described as a slimy green alien. His flight suit was modeled after WW2 German fighter pilot suits, curiously worn by pilots of the rebellion as well.