After just a few weeks since German invasion thousands of Soviet citizens desired to serve in the German army. The number of such volunteers was constantly increasing. There are no precise data, but approximately 1.500.000 Soviet citizens had served in Wehrmacht. From the very first day of the World War II a lot of Soviet captives and deserters suggested their help to Germans in subsidiary services. Germans called those volunteers Hiwi (from Hilfswillige-voluntary aide). Those volunteers served as drivers, cooks, hospital attendants, stable-men in the rear services. Thus they gave Germans the possibility to serve in the forward position. And in the battle sub-units Soviet volunteers served as ammunition carriers, sappers and messengers. Hiwi had personal arms for the case of danger. Originally Hiwi continued to wear Soviet uniform and badges of rank, but gradually they were given the German uniform. Sometimes only the armband with the words "Im Dienst der Deutschen Wehrmacht" was the proof of the fact that Hiwi belonged to Wehrmacht.
Another category of volunteers -- Osttruppen -- was joined in battalions (Ostbataillonen) that were the sub-units of German army. The first battalions were formed according to German commanders' initiative. Soviet citizens of the non-Russian nationalities were the bases of those battalions: Ukrainians, Balts, Caucasians and Cossacks. The task of the 'Ostbataillonen' was to guard the rear. In November 1941 the first six battalions were formed as a part of the "Centre" army group, and soon the high command of Wehrmacht gave its official permission to form such sub-units but with some restrictions. The restrictions did not permit to form the battalions with more than 200 servicemen in them, and they could be used only for guarding the rear.
By the end of 1941 the formation of several Asian and Caucasian legions (Ostlegionen) had began. Their structure was identical to the one of the western legions. In summer of 1942 Germans tried to put their mixed uniform in order. But they could not achieve the unification. There were three types of the badges of rank. The first one was to be used in Russian and Ukrainian sub-units, the second -- in Asian sub-units, the third -- in Cossack sub-units. There were two types of shoulder-straps: for Russians, Ukrainians, Cossacks and for Asians. But the practical use of all these badges of rank became a real mess. The cockades and chevrons were also designed for each nationality. The German eagle (Hoheitsabzeichen) was replaced by the insignia -- swastika in rhombus with stylized wings. The stripe was made with grey threads on the steel-blue field. But the stripe was not very popular.
The 5th degree award for courage and merits was established instead of German awards. But in reality the majority of the volunteers was decorated by customary German awards. In 1944 Germans permitted officially to decorate Ostbataillonen soldiers with Third Reich awards.
In June of 1942 the antipartisan detachments and so called Jagd-units were formed by division headquarters. They were small and good equipped with automatic guns and consisted of trustworthy and trained fighters. By the end of 1942 almost every division on the Eastern front had one or two Eastern companies, and corps had Ostbataillon. The major part of those sub-units had standard numbers: 601-621, 626-630, 632-650, 653, 654, 656, 661-669, 674, 675 and 681. Other battalions had line regiments numbers (510, 516, 517, 561, 581, 582), corpses numbers (308, 406, 412, 427, 432, 439, 441, 446-448, 456) and divisions numbers (207, 229, 263, 268, 281, 285). It depended on the place they had been formed at.
After the defeat under Stalingrad the German command began to form SS volunteers divisions in Western Ukraine and the Baltic states. It was done under the motto of 'crusade against bolshevism'. In the early 1944 the Ukrainian, Estonian and two Latvian SS-divisions had been formed. The Byelorussian krai defences were formed in Byelorussia, the Lithuanian territorial corps -- in Lithuania. Since May 1944 Hitlerjugend began to recruit teenagers (15-20 years old) in Ukraine, Byelorussia and the Baltic states. The majority of young volunteers served in subsidiary units of military aircraft forces and anti-aircraft defences. There were more than 16.000 servicemen in those units.
The majority of Ostbataillonen were dislocated in the West and were taken immediately into action when allies got off in Normandy. Their poor armament was the cause of heavy losses, but they proved to be trustworthy. From 1941 till 1945 2 million Soviet citizens fought on the German side.