Krebs was a soldier in the Wehrmacht during World War II, before becoming a Skorzeny Werwolf commando. After the Ardennes offensive he stayed behind Allied lines operating with his commando group under the command of Hugo von der Drache. The earned the nickname "Der Zwangsman," or, "the Persuader" after his ruthless techniques of interrogation via torture. After Germany's defeat he returned to a civilian life in his homeland until he was found, along with many of his fellow soldiers, by Hugo Drax. Drax used him and the others to build his Moonraker missile. In order to prevent anyone from recognizing him, he shaved his head and grew a moustache
James Bond is introduced to Krebs when he first arrives at Drax's compound as his new security overseer and catches Krebs snooping through his room. Later, whilst talking to Gala Brand, she tells Bond that Krebs has done the same to her in the past. The pair catch him in the act and Bond beats him in combat, kicking him sharply in the forehead. He is reported by the pair to Drax who places him under house-arrest until the launch of the Moonraker experiment. The next day, while investigating the exhaust ports, a controlled landslide nearly kills Bond and Gala which was carried out by Krebs on Drax's order.
He later accompanies Drax and Gala to London and realizes that Gala has discovered Drax's scheme with the Moonraker missile's co-ordinates. He restrains her and binds her in the rear of Drax's car. When Bond pursues them he captures Bond and helps Drax bring them back to Dover.
- Krebs bears the same name as Adolf Hitler's last Chief of Staff.