Krebs and Baumer were both soldiers in WW1. However they were on opposing forces. Krebs fought for the Americans and Baumer for the Germans. Krebs survived the war and returned home in 1919. Baumer died in 1918. When Krebs got home, he felt distant, like he did not fit in anymore. This is kind of how Baumer felt when he went on leave during the war to visit his family. Disconnected, like they did not belong. I believe that Baumer did not like the combat, he more enjoyed the down time hanging out with his comrades. Krebs really enjoyed the thrill of combat. Krebbs cannot get that thrill in civilian life, but he cant tell that to anyone because that would make him look crazy which distants him even more from the rest of society.