Dieter Jovanovic
Dieter Jovanovic was a German man from Berlin during the time of the Wiemar Republic.
Jovanovic lost his father and many friends during the First World War. Already shaken by their deaths, he was further embittered by the peace settlement demanding Germany pay reparations which strangled much of the country into poverty.
In August 1925, Jovanovic encountered a lost Cyberman and gained control over its actions. He used it to infiltrate the film set of Fritz Lang's Metropolis by passing it off as an advanced puppet that could play the film's robot. Jovanovic was intent on ceasing production completely because the film was to promote a message of peace, even though the current peace experienced by Germany was a humiliation. Instead, he believed that Germany's only way forward was revenge.
Jovanovic had the Cyberman murder the film's lead, Olaf Richter, and attack Lang, his assistant Anna Dreyfus, and the Ninth Doctor. However, with the Cyberman damaged, the Doctor helped it resist its Cyberman conditioning. It broke free of Jovanovic's control and strangled him to the point of unconciousness. He was subsequently arrested and confessed to his crimes.
Despite his arrest, the Ninth Doctor lamented that a growing number of Germans held the same beliefs as Jovanovic, all falling prey to a "bug" destined to bring about terrible future events. Metropolis was also a huge cinematic failure with contemporary audiences, and its message of peace failed to resonate. It would only be residcovered and re-evaluated decades after release. (AUDIO: Monsters in Metropolis)