The Soldier had claimed HK-47, who had completed an assassination mission for Revan but was damaged and unable to return to his master, as his 'booty'. The Mandalorian repaired HK-47 (rather poorly, the droid mentioned) to the extent he was capable of and began using his assassination protocol to raise his rank.
Eventually the Soldier's desire for power soon got the better of him. He then ordered HK to assassinate an unidentifiedMandalore who ruled between Mandalore the Ultimate and Canderous Ordo. He failed and was captured by the Mandalore, who reprogrammed him and sent him after his former master, who was successfully obliterated. Since HK-47 was programmed to shut down whenever his current master died, he deactivated himself after killing the Mandalorian, and was sold to Bochaba the Hutt, a crime lord on the planetSleheyron.