Transfer is a gray jackal or wolf serving as the primary antagonist. Hired by Mr. Sullivan, head of the Bank of England, his mission is to sabotage Willy Fog's circumnavigation journey and ensure Fog loses the wager. A master of disguise, Transfer employs impersonation tactics to mislead or endanger Fog and his companions; his glass eye, often catching light to reveal his identity, remains his only consistent distinguishing feature.

His sabotage methods encompass deliberate misinformation, physical traps, and indirect attacks. Specific actions include incapacitating the elephant owner Parsi in India to impersonate him and lead Fog's group astray, drugging Rigodon in Hong Kong after impersonating Inspector Dix, and orchestrating environmental hazards across North America—such as a buffalo stampede, bridge collapse, and train attacks—by manipulating local groups like Native Americans. He further extends the Pacific crossing by contaminating a ship's drinking water, forcing a detour to Hawaii, and later setting the vessel ablaze to strand the group in Mexico, necessitating their hot-air balloon journey.

Transfer's actions adapt events from Jules Verne's original novel to maintain Fog's heroic portrayal; for instance, he orchestrates the theft of the elephant Koa to absolve Fog of morally questionable acts present in the source material. He serves as a narrative device ensuring Fog remains an unblemished protagonist while introducing new conflicts. Physically described with gray fur and a glass eye that gleams under light, Transfer exhibits no significant character development or background beyond his function as Sullivan's agent. He appears in all 26 episodes except the premiere, consistently furthering obstacles without personal arcs or spin-off media involvement.