Jumo Pyleen was a mechanic for astro-race pilot Skip Pyleen and an employee of the brothers Hop Pyleen. He was part of Skip's support team during the race in which the Hyposlip 500 lightspeed podule was first used. When a group of Rakkonoids attacked the race, Jumo assisted the Tenth Doctor and Rose Tyler in pursuing the aliens, who were trying to buy the secrets of the Hyposlip-500 technology from Skip. After the Doctor defeated the plot, Jumo told him that his bosses would reward them if they hadn't already disappeared. (COMIC: Death Race Five Billion)