Grataa was a Kaleesh male who participated as a representative of the Great Hunt. He existed during the time of the Cold War. He was responsible for admitting an unidentified bounty hunter into the Great Hunt competition, which took place on the planet of Nal Hutta. The bounty hunter's associate, Mako, gave him the nickname "Skullface".
In the year 3643 BBY, Grataa journeyed to Nal Hutta and visited the palace belonging to Nem'ro the Hutt to observe the elimination process. After Tarro Blood murdered Braden and Jory, Grataa reviewed a recording of the event and initiated an investigation. Upon encountering the bounty hunter named Rarsk, he provided the chosen Trandoshan with instructions pertaining to the Great Hunt. However, Mako became suspicious after she and her partner eliminated Rarsk, who had been tracking a Republic scientist. Upon their return to the palace, Mako displayed initial nervousness in his presence, but the Kaleesh reassured her and clarified the rationale behind their actions. Subsequently, he furnished the hunter and Mako with a pass that granted them access to a shuttle destined for Dromund Kaas, the capital of the Sith Empire. Given that Blood had not violated any tournament regulations, Grataa pledged to maintain surveillance over the Mandalorian.