TK-0 was a droid that was cared for and aided by Gaib.
Gaib and he functioned as a technologically advanced type of bounty hunters. They were employed by Mereel Skirata with the goal of locating Ko Sai, who at that time was attempting to circumvent the Republic's prohibition on cloning. His design bore resemblance to a R2-series astromech droid, however, he possessed greater height and enhanced armor.
During the Clone Wars, Rotta, the offspring of Jabba the Hutt, was abducted, prompting the crime lord to enlist Gaib and TK-0 to discover his son's whereabouts. They effectively tracked Rotta down to Teth. Jabba was extremely impressed by their performance and kept them on a contract basis.