Babi Yar no relation SS Einsatzgruppen
Walter Karl Ernst August von Reichenau (8 October 1884 – 17 January 1942) was a field marshal in the Wehrmacht of Nazi Germany during World War II. Reichenau commanded the 6th Army, during the invasions of Belgium and France. During Operation Barbarossa, the invasion of the Soviet Union, he continued to command the 6th Army as part of Army Group South as it captured Ukraine and advanced deep into Russia.
While in command of the 6th Army during Operation Barbarossa in 1941, he issued the notorious Severity Order which encouraged German soldiers to murder Jewish  civilians on the Eastern Front. Reichenau's troops cooperated with the SS Einsatzgruppen in the commission of the massacre of over 33,000 Jews at Babi Yar, and assisted with other crimes against humanity that occurred in areas under his command during the Holocaust.Interwar period
After the war, he joined the Grenzschutz Ost Freikorps as a General Staff officer, serving in Silesia and Pomerania. In 1919 Reichenau joined in the newly established Reichswehr of the Weimar Republic. The officer corps of the new armed forces' was limited to 4,000, and there was to be no General Staff. Reichenau took a post in the Truppenamt, which was the "underground" equivalent of the General Staff formed by Hans von Seeckt. He was promoted to Major in 1924, to Lieutenant Colonel on 1 April 1929 and Colonel on 1 February 1932. In 1930, Reichenau was appointed Chief of Staff to the Inspector of Signals at the Ministry of the Reichswehr. He was later introduced to Hitler in April 1932 by his uncle, a diplomat. Extremely ambitious, he saw the Nazi Party as a revolutionary vessel in which he could propel his career and so broke with the pro-Monarchist politics of the Prussian military caste and became a devoted Nazi.As an outspoken ally and advocate of Hitler and the Nazi Party, Reichenau soon ran afoul of cabinet member and eventual Chancellor Kurt von Schleicher, who used his authority to have him transferred out of his prestigious posting in Berlin to the headquarters of the military district of East Prussia, a relative backwater. In East Prussia Reichenau served under General Werner von Blomberg, a fellow exile of Schleicher's. Reichenau and Blomberg became political allies within the army and it was Reichenau who introduced Blomberg to Hitler. Blomberg, who had a reputation of being manipulated by Reichenau, was captivated by Hitler and both men soon used their connections with the Nazi party to advance. When Hitler came to power in January 1933, Blomberg became Minister of War. One of his first acts was to promote Reichenau to head the powerful Ministerial Office, acting as liaison officer between the Army and the Nazi Party. He played a leading role in persuading Nazi leaders such as Göring and Himmler that the power of Ernst Röhm and the SA must be broken if the army was to support the Nazi-led government. This led directly to the "Night of the Long Knives" of 30 June 1934.
In 1935, Reichenau was promoted to lieutenant general (Generalleutnant) and was also appointed to command the military forces in Munich. Reichenau was one of Hitler's favorite Generals and his first choice for commander-in-chief of the Heer in 1934, but internal army politics resulted in General Werner von Fritsch getting the post.Reflecting Reichenau's preference for assignments of political matter, Blomberg sent Reichenau to China in May 1934 to support General Alexander von Falkenhausen's existing military assistance mission.  Konstantin von Neurath, the Foreign Minister, and German ambassador to Japan Herbert von Dirksen, raised objections to Reichenau's posting, fearing that the assignment of an officer of his stature could imperil Germany's relationship with Japan.
In 1938, after the Blomberg–Fritsch affair, in which Fritsch was forced out of the Army command, Reichenau was again Hitler's first choice for head of the Heer, but older leaders such as Gerd von Rundstedt and Ludwig Beck refused to serve under Reichenau, and Hitler again backed down.