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 Dok during Eren Yeager'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.
Waltz attends Erwin Smith's trial alongside Nile, and is present when it is reported that Wall Rose has been breached by the Colossus and Armored Titans. He and his comrades are astounded when the royal officials present order that all refugees from Rose are kept from entering Wall Sheena, and does not attempt to stop Darius Zackly's forces from arresting the officials.