During this period Hitler collaborated with a range of figures, not all of whom were party members, in an informal and often non-hierarchical way. His closest associate was Rudolf Hess, a First World War veteran who had grown up in Egypt; the date of their first encounter (which was probably in May 1920) is disputed, but we know for a fact that he joined the NSDAP in July 1920.
A key interlocutor was the Reichswehr officer Ernst Rohm, whose meetings are documented from early 1920, though the first contacts may have taken place a lot earlier.
Hitler had frequent dealings with the staff of the Völkischer Beobachter, especially its executive editor, the playwright Dietrich Eckart, and his deputy Alfred Rosenberg, a Baltic German refugee from the Russian Revolution, who would influence Hitler’s view of the Soviet Union; the editor was his old regimental comrade Hermann Esser. In a rare gesture, Hitler explicitly acknowledged his debt to Eckart for his help with the Völkischer Beobachter, and to Rosenberg for his ‘theoretical deepening of the party programme’.
In late 1920, Hitler met Max Erwin von Scheubner-Richter, who had witnessed and been appalled by the massacre of the Armenians as a German consul in the East Anatolian town of Erzurum during the First World War. It was probably from him that Hitler got his determination that the Germans should not become a ‘people like the Armenians’, that is, the butt of foreign oppressors.