The Unknown Soldier is probably the darkest of DC's classic war comics (at least when David Micheline took over). The great Joe Kubert originally conceived of the character as the ultimate American soldier. In each story he would assume a disguise and then accomplish some suicide mission. The high concept being that because of the disguise anyone of our soldiers could turn out to be him in disguise, thus elevating our entire armed forces, just painfully patriotic, fortunately this was a WWII comic so that's ok.
And then the writer changed and suddenly the Soldier was transformed into a broken man who was only sent on the army's most reprehensible missions. Instead of bolstering the morale of the entire army he would have to assassinate a priest. Both interpretations of the character are present in the Showcase Presents edition, and both of them provide for many excellent stories. But it is incredibly jarring when the switch occurs.