Germany lost its colonies 1918. The "Askaris" and so on never had the German nationality. The German wifes with "halfblack" children had a bad life in postwar Germany and naturally their children too. Nevertheless it could have been possible that their by law German sons served in the army. I never had seen any and I served late 70`s. But let me say that I grew up in Erlangen near Nuremberg where I met several of those typical
boys and girls and it was so astonishing and amusing for us to hear them speaking the typical franconian dialect. So far so good. I think they had a bad childhood. In my age (51) I have seen none making career.