I'm afraid I can't tell you too much about Japan, but the Germans made extensive use of peoples from the territories that it occupied during the war. This phenomenon was more pronounced later in the war, particularly after the reversals in the winter of 1942-1943. Prior to the defeat at Stalingrad, civilians from the occupied territories were much more likely to be rounded up and deported to Germany for work. Even in this role as forced laborers they still served as a kind of soldier-by-proxy, as each foreign worker freed up a German to fight at the front. I can't give you hard numbers on the participation of foreigners in the Wehrmacht, but foreign civilians made up as much as a quarter of Germany's domestic industrial workforce by the end of the war. Even in this early period, German military and police forces abroad did draw on so-called Hilfwilliger, locals who volunteered their help to the occupier. Despite ideological resistance to incorporating them into regular fighting formations, by 1942 pressures on manpower led to a great many of them being brought into the Wehrmacht. In fact, these Hilfswilliger made up a quarter of the 6th Army during the Battle of Stalingrad. An important turning point came in February 1943, when Goebbels moved to re-position the regime's propaganda line regarding Eastern peoples (in the context of his propaganda campaign for Total War). Whereas earlier the line had been that Slavs were Untermenschen, Goebbels suggested that they, like Germans, had a duty to defend Europe against the onslaught of Bolshevism and that they should participate in what was pitched as a crusade to rescue European culture. Shortly thereafter Himmler approved the creation of Waffen-SS units composed entirely of non-Germans. The Kaminsky Brigade, some 10,000 former Soviet soldiers, was one of these Waffen-SS units and they participated in the brutal suppression of the Warsaw uprising. Still Himmler, along with Hitler, resisted proposals to create a substantial all-Russian fighting formation under the command of the captured Soviet general Andrey Vlasov. Himmler finally changed his tune in September 1944 and helped to push through the creation of the Russian Liberation Army, commanded by Vlasov and filled out with 40,000 former Soviet soldiers. The Russian Liberation Army first saw combat on the Oder in February 1945. Thereafter they retreated to Prague and promptly switched sides, fighting the Waffen-SS there during the Prague uprising.