An ex-Luftwaffe pilot, Voss had joined the French Foreign Legion and then deserted to join the war-mongering syndicate. He had been employed by the syndicate on various bombing missions using stolen military aircraft. On one occasion, while attempting to bomb a village in Abyssinnia using a stolen French bomber, Voss had been shot down by the French Air Force. Taken into custody by the French authorities, Voss had refused to talkk, saying he would be killed if he revealed anything about his employers. While awaiting trial, Voss had managed to escape in a manner which indicated that he had powerful friends.
Voss returned to flying for the syndicate and was shot down again. this time while bombing a village in Indo-China in a stolen American bomber. This time, under pressure from French authorities, he confessed to working for a multi-national unit of soldiers of fortune. He had been employed with a generous lump sum and the promise of good pay provided he would take orders and not ask any questions. He served on secret airstrips in Africa and Asia but claimed that he never knew who he was fighting nor what he was fighting for. The only man of authority he knew was one Capitan Klein, also a German and a Legion deserter.
Voss was put on trial but got off with a light sentence with the help of a lawyer named Jules Raban and then disappeared.
When Biggles and Ginger, having gone undercover to join the French Foreign Legion, were induced to desert by Sergeant Voudron, they were taken to see Jules Raban at his residence, the Villa Mimosa in Zebrit. Raban formally inducted Biggles and Ginger into the war-mongering syndicate as pilots and introduced them to Voss who would take them to the secret squadron. It turned out that after his brief jail term, Voss had resumed working for the syndicate.
Voss led Biggles and Ginger to the airfield of the French Air Force Escadrille 77 with the intention of stealing a Breguet light bomber for their journey to the secret squadron. However Voss was overconfident and had overlooked the fact that, after so many thefts, the security at French bases might have been tightened. They got into the cockpit of a bomber easily enough but were ambushed by French security forces almost as soon as the engines were started. Voss, at the controls of the bomber, was killed during the take-off run. Biggles had to struggle to take over the controls to complete the take off. The bomber got away but was soon intercepted by French fighters and shot down not far from the airfield with Biggles and Ginger in it.