The E-100 project was commissioned in order to standardize parts. It was to be built in classes of varying sizes to replace existing vehicles. Different types were designated a number indicating their weight in tons: E 10, E 25, E 50 (Panther replacement), E 75 (Tiger replacement) and E 100.

Of these only the E-100 project was actually started. Construction of the E-100 prototype proceeded slowly at Henschel's test plant after Hitler's order to cease work on super-heavy tanks, and at the end of the war only the bare hull and suspension were completed.