Hans Kammler was an SS-Obergruppenführer responsible for Nazi civil engineering projects and its top secret V-weapons program. He oversaw the construction of various Nazi concentration camps before being put in charge of the V-2 rocket and Emergency Fighter Programs towards the end of World War II. Kammler disappeared in May 1945 during the final days of the war. There has been much conjecture regarding his fate.

Obergruppenführer was a paramilitary rank in Nazi Germany that was first created in 1932 as a rank of the Sturmabteilung (SA) and adopted by the Schutzstaffel (SS) one year later. Until April 1942, it was the highest commissioned SS rank after only Reichsführer-SS. Translated as "senior group leader", the rank of Obergruppenführer was senior to Gruppenführer. A similarly named rank of Untergruppenführer existed in the SA from 1929 to 1930 and as a title until 1933. In April 1942, the new rank of SS-Oberst-Gruppenführer was created which was above Obergruppenführer and below Reichsführer-SS.