The Waffen-SS grew from three regiments to over 38 divisions during World War II, and served alongside the Heer (regular army), Ordnungspolizei (uniformed police) and other security units. Originally, it was under the control of the SS Führungshauptamt (SS operational command office) beneath Reichsführer-SS Heinrich Himmler. With the start of World War II, tactical control was exercised by the High Command of the Armed Forces (OKW), with some units being subordinated to Kommandostab Reichsführer-SS (Command Staff Reichsführer-SS) directly under Himmler's control.
Initially, in keeping with the racial policy of Nazi Germany, membership was open only to people of Germanic origin (so-called Aryan ancestry). The rules were partially relaxed in 1940, and later the formation of units composed largely or solely of foreign volunteers and conscripts was authorised. These SS units were made up of men mainly from among the nationals of Nazi-occupied Europe. Despite relaxation of the rules, the Waffen-SS was still based on the racist ideology of Nazism, and ethnic Poles (who were viewed as subhumans) were barred specifically from the formations.
Members of the Waffen-SS were involved in numerous atrocities. At the post-war Nuremberg trials the Waffen-SS was judged to be a criminal organisation due to its connection to the Nazi Party and direct involvement in numerous war crimes and crimes against humanity. Former Waffen-SS members were denied many of the rights afforded to the military veterans. An exception was made for Waffen-SS conscripts, who were exempted because they were not volunteers. About a third of the total membership were conscripts.
The origins of the Waffen-SS can be traced back to the selection of a group of 120 SS men on 17 March 1933 by Sepp Dietrich to form the Sonderkommando Berlin. By November 1933 the formation had 800 men, and at a commemorative ceremony in Munich for the tenth anniversary of the failed Munich Putsch the regiment swore allegiance to Adolf Hitler. The oaths pledged were "Pledging loyalty to him alone" and "Obedience unto death". The formation was given the title Leibstandarte (Bodyguard Regiment) Adolf Hitler (LAH). On 13 April 1934, by order of Himmler, the regiment became known as the Leibstandarte SS Adolf Hitler (LSSAH).
The Leibstandarte demonstrated their loyalty to Hitler in 1934 during the "Night of the Long Knives", when the Nazi regime carried out a series of political killings and the purge of the Sturmabteilung (SA). Led by one of Hitler's oldest comrades, Ernst Röhm, the SA was seen as a threat by Hitler to his newly gained political power. Hitler also wanted to conciliate leaders of the Reichswehr (the Republic's army) and conservatives of the country, people whose support Hitler needed to solidify his position. When Hitler decided to act against the SA, the SS was put in charge of eliminating Röhm and the other high-ranking SA officers. The Night of the Long Knives occurred between 30 June and 2 July 1934 and saw the killing of up to 200 people. This included almost the entire SA leadership, effectively ending its power. This action was largely carried out by SS personnel (including the Leibstandarte), and the Gestapo.
In September 1934, Hitler authorized the formation of the military wing of the Nazi Party and approved the formation of the SS-Verfügungstruppe (SS-VT), a special service troop under Hitler's overall command. The SS-VT had to depend on the German Army for its supply of weapons and military training, and they had control of the recruiting system through local draft boards responsible for assigning conscripts to the different branches of the Wehrmacht to meet quotas set by the German High Command (Oberkommando der Wehrmacht or OKW in German). The SS was given the lowest priority for recruits.
Even with the difficulties presented by the quota system, Heinrich Himmler formed two new SS regiments, the SS Germania and SS Deutschland, which together with the Leibstandarte and a communications unit made up the SS-VT. At the same time Himmler established the SS-Junkerschule Bad Tölz and SS-Junkerschule Braunschweig for military training of SS officers. Both schools used regular army training methods and mainly used former army officers as instructors.