Gerard commands as a high-ranking figure within the Ahnenerbe, a Nazi-aligned group dedicated to resurrecting the Third Reich by securing the Eclipse—an advanced power generator crafted by a forgotten civilization. His obsessive quest to earn Adolf Hitler’s approval fuels his every move, driven by the conviction that the Führer survived World War II and hides in South America. This fixation compels him to manipulate collaborators, discard hindrances, and pursue the Eclipse at any cost.

He forges an uneasy alliance with Lambert, a professor sharing his ambitions, though their dynamic fractures under Gerard’s relentless belittlement. He derides Lambert’s capabilities compared to Professor Bresson, the diary’s author, and mocks Laetitia, Lambert’s adoptive granddaughter, for her vulnerabilities. When Laetitia uncovers their plot, Gerard coldly demands her elimination, only to be countered by Lambert’s defiance.

After activating the Eclipse, Gerard chooses to deliver it to Hitler rather than obliterate Berlin instantly, exposing his unwavering loyalty to the Nazi ideology. News of Hitler’s alleged survival hardens his resolve, prompting him to relocate the device to an Ahnenerbe stronghold in Brazil. His scheme unravels when Lupin III, disguised as Hitler, exposes the Führer’s death and the fabricated evidence sustaining Gerard’s delusion.

In their final clash, Gerard assaults Lupin aboard the Eclipse but falters against the thief’s cunning. Lupin sabotages the generator, unleashing a micro black hole that engulfs Gerard. His end mirrors the futility of his fanaticism and ruthless calculus, as his betrayals and escalating brutality culminate in self-destruction. Gerard’s trajectory epitomizes the peril of unyielding ambition wedded to a shattered ideology.