Waffen SS and the Regiment III of Cossacks during Warsaw Uprising. The regiment was composed of both Don and Kuban Cossacks.
The first collaborators were formed from Soviet Cossack POWs and deserters after the consequences of the Red Army's early defeats in the course of Operation Barbarossa. After the horrors of Collectivization and Decossackization, in summer of 1942, many of the Germans reaching Kuban were greeted as liberators. Many Soviet Kuban Cossacks chose to switch to the German side either when in POW camps or on active service in the Soviet Army. For example, Major Kononov deserted on August 22, 1941 with an entire regiment and was instrumental in organizing Cossack volunteers in the Wehrmacht.
Some Cossack emigres, such as Andrei Shkuro and Pyotr Krasnov chose to collaborate with the Germans as well and stood at the helm of two Cossack divisions on German service. However, most volunteers came after the Germans reached the Cossack homelands in summer of 1942.
The Cossack National Movement of Liberation was set up in hope of mobilizing opposition to the Soviet regime with an intent to rebuild an independent Cossack state.
While there were several smaller Cossack detachments in the Wehrmacht since 1941, the 1st Cossack Division made up of Don, Terek and Kuban Cossacks was formed in 1943. This division was further augmented by the 2nd Cossack Cavalry Division formed in December 1944. Both divisions participated in hostilities against Tito's partisans in Yugoslavia. In February 1945, both Cossack Divisions were transferred into the Waffen-SS and formed the XVth SS Cossack Cavalry Corps. At the end of the war, the Cossack collaborators retreated to Italy and surrendered to the British army, but, under the Yalta agreement, were forcibly repatriated with the rest of the collaborators to the Soviet authorities and some executed.