Buster Keaton as Kringelein.

From the IMDB trivia: "Buster Keaton was first choice to play the Lionel Barrymore part".

It's interesting to speculate what a different movie this would be with Keaton as one of the central stars. For instance I picture a somewhat different ending for The Baron. Instead of being murdered by Preysing, Kringelein and the Baron would be standing side by side and the hotel facade falls on them. Kringelein is left untouched as an open window falls on him. Unluckily for the Baron though that window is too narrow for both of them and he is squished.