Arnim Zola sought to overcome the mobility problems that HYDRA's armored vehicles had when crossing difficult terrain. Inspired by the old world décor of Castle Zemo, Zola decided to create a modern knight in armor. Zola created the first bipedal walking tank in history; a single-pilot, highly armored battle suit. Due to its historical inspirations, Zola dubbed it Iron Cross.
The armor was worn by Helmut Gruler. He used the armor to capture Captain America after his battle against Baron Wolfgang von Strucker left them both unconscious. He later attempted to defend the Red Skull, who was using the Tesseract to wake the Sleeper. Rogers was able to deflect the suit's blasts with his shield, slowing it down and rendering it vulnerable. The Red Skull intervened by firing his own grenades, which had the unintended result of damaging the suit even further and caused it to shut down.
The Iron Cross armor possessed a cannon that fired concussive sound, which was used to deafen and disorient enemies and cause significant damage to the inner ear. This compensated for the armor's slow speed by allowing it to crush the opposition while they were in agony from the sound.