II. "Gruppe" had been ordered to the Eastern Front in preparation for Case Blue, the strategic summer offensive in southern Russia. While based at Pilsen, "Hauptmann" Kurt Brändle took over command of the "Gruppe" after the former commander "Hauptmann" Karl-Heinz Krahl had been killed in action over Malta. The "Gruppe" was then deployed on the left wing of Army Group South where it was based at Chuhuiv near the Donets on 19 May. There, Fuß served with the "Gruppenstab" as an adjutant to Brändle.