Helmut von Mephisto claimed to be a descendant of Frederick the Second of Prussia. By Mephisto's own admission, his mother had had him locked up for his own good because he was a "bad boy".
Mephisto was trained at Castle Wewelsburg, Heinrich Himmler's SS school and was awarded the Totenkopfring. At some point the Nazis outfitted him with a formidable mechanical right arm that could fire electrical energy.
He had achieved the rank of Obergruppenführer by 1941 when he sent a telegram from Berlin to Agent Z-733 to spy on Indiana Jones who was in Mexico assisting Colonel Musgrove. Ironically, by the time Mephisto traveled to Mexico as the head of a team looking to research ancient weapons, Jones had been assigned the task of finding out what held the Nazis' interest to which Mephisto's name was connected.
Behind the scenes
Helmut von Mephisto was created by J. W. Rinzler for Indiana Jones and the Mystery of Mount Sinai. However, the names can be traced back to Mephisto and Helmut Gutterbuhg, antagonists present in Chris Columbus' unrealized Indiana Jones and the Monkey King script, one of the screenplays considered for the third Indiana Jones film before the production settled on the plot of Indiana Jones and the Last Crusade. The idea of a Nazi character with a mechanical arm was also present in the Monkey King draft but the idea itself dates back to Raiders of the Lost Ark with concept art by Ron Cobb showing Arnold Ernst Toht with such a limb.
- Indiana Jones and the Mystery of Mount Sinai (First appearance)