Gol Clutha was the captain of a mercenary team.
On a job, they overpowered a Sontaran timeship by killing 300 Sontaran warriors with halisiton gas. Gol took great pleasure in this, as she despised Sontarans. They were hired by the Prometheans to transport a cargo of psychic metal containing Ian Chesterton and Barbara Wright, and were promised fifty million credits for the job. Whilst celebrating completing the job, she retired to her private quarters and found the Eleventh Doctor waiting for her. He berated her for ruthlessly murdering the Sontarans. She tried to kill him with a traulian mind-spike, which would fry his brain. The Doctor told her that he had flipped the polarity so that it would zap the user, not the target. However, Gol failed to believe him, and accidentally stunned herself in an attempt to kill him. (COMIC: Hunters of the Burning Stone)
Gol and her "boys" were hired by Josiah W. Dogbolter, who came to Stockbridge in 2016 to have them escort the Twelfth Doctor to him. Dogbolter ordered Gol to kill the Doctor, when Frobisher knocked out Gol and the other mercenaries. (COMIC: The Stockbridge Showdown)