Herr Gruber was a high ranking Nazi official that was active during World War II. By the summer of 1942, when the Allied Forces started taking a heavy toll on German weapons factories, Gruber was ordered by Adolf Hitler to come up with a solution. Gruber came up with the idea to build underground factories beneath the forests of Germany and using prisoners of war as slave labor to construct these hidden factories.
Gruber's plan was soon learned by the wartime hero known as the Destroyer who soon found the location of one of these factories as it was being constructed. The Destroyer rallied the slaves into a revolt and would personally knock out Gruber. The Destroyer left Gruber knocked out in the factory as he wired its cache of explosives to go off. Gruber was killed in the ensuing explosion.