Otto was a German soldier stationed at the Nazi Tanis digsite outside Cairo, Egypt during their search for the Ark of the Covenant in 1936, led by Colonel Herman Dietrich, French archaeologist René Emile Belloq and Gestapo Major Arnold Ernst Toht. Otto guarded the entrance to Belloq's tent where the captive Marion Ravenwood was held.
In 1936, Otto, a Nazi soldier, was stationed at the German excavation of Tanis outside Cairo, Egypt in pursuit of the Ark of the Covenant. Otto served under Colonel Herman Dietrich, French archaeologist René Emile Belloq and Gestapo Major Arnold Ernst Toht during the search, and stood watch outside Belloq's tent.
When Belloq prepared to question the American captive Marion Ravenwood on her knowledge of the headpiece to the Staff of Ra which was key to finding the lost Ark, she was untied by Belloq's servant but immediately attempted to flee. However, Otto simply stepped into her path clutching a rifle so that she never made it beyond the entrance of the tent. Nevertheless, Otto was soon dismissed by Belloq along with his servant as the archaeologist was confident that the idea of fleeing into the desert was enough of an incentive for Marion to stay.
Behind the scenes
The role of Otto was provided by Christopher Frederick in Raiders of the Lost Ark. The character should not be confused with the Second Nazi, later named Otto, as played by Matthew Scurfield earlier in the film during the bar fight at The Raven.
The Complete Making of Indiana Jones misindentifies Dietrich as Otto in a photo of Steven Spielberg going through the tent scene with Ron Lacey (Toht), Wolf Kahler (Dietrich) and Anthony Higgins (Gobler).
Regarding the identity of the character of Otto in the film, Lucasfilm Story Group's Pablo Hidalgo writes:
"We found a call sheet with Christopher Frederick for one day only -- a day of shooting inside Marion's tent. Because all the other characters in the call sheet are identified, we figure he is either the Arab servant that sets up Belloq's dinner, or the German soldier that pushes Marion into the tent, but there's currently no way to identify him beyond that."
The website Aveleyman.com however reveals Christopher Frederick's appearance, in an episode of BBC Plays, Caught on a Train, as a German guard. Although the character of Otto is not clearly seen in the tent scene, Frederick's facial shape most closely resembles the German soldier rather than the Arab servant.