Karl was a mercenary employed by the Dalek Emperor to capture the American envoy with the help of the Cybermen. He tricked the Sixth Doctor into going to Altair III instead of following them to the Dalek flagship. He also managed to get the Doctor away from Bar Galactica before the Daleks lost him. After the Daleks betrayed him and killed Madame Delilah, he helped the Doctor defeat them. (AUDIO: The Ultimate Adventure)