Waltz is a man of average height and build, with short blond hair. He is only ever seen wearing the standard Military Police uniform.
Waltz accompanies Nile Dawk during Eren Jaeger's trial. When Eren attempts to argue on his own behalf, Waltz prepares to execute him on Nile's order, only to be interrupted by Levi, who begins savagely beating Eren.
After the Scout Regiment is forced to hand Eren over to the Military Police due to their failure during the 57th Exterior Scouting Mission, Waltz is one of the soldiers tasked with guarding Eren while he is being transported. When two Titans suddenly appear inside Stohess, Waltz attempts to stop his captive from exiting his carriage only to realize that he is a decoy.