Black milk of daybreak we drink it at evening we drink it at midday and morning we drink it at night we drink and we drink (lines 1-3)
These opening lines are the poem's refrain. They are repeated at the beginning of each new turn of the "fugue." The war experience for the camp prisoners unique (and uniquely terrible) because, unlike a battle that must end at some point, there is never any let-up in the fight for survival. There is no time during the day when they are not forced to drink "black milk."
he whistles his Jews into rows has them shovel a grave in the ground he orders us strike up and play for the dance (lines 9-10)
The Jews are forced to do the dirty work for the Nazis. Not only was forcing the prisoners to dig graves considered efficient, but it also wore down the spirit and morale of the prisoners. It was part of the strategy in the Nazi war on the Jewish people.
He shouts jab this earth deeper you lot there you others sing up and play he grabs for the rod in his belt he swings it his eyes are blue (lines 17-18)
The guard is portrayed as more and more inhumane as the poem goes along. Here he is shown beating the prisoners, and his blue eyes are a symbol of cruelty, rather than the ideal that the Nazis hoped for. He is like a musical conductor, ordering one group to dig and the other to play music.
He shouts play death more sweetly Death is a master from Deutschland (line 25)
Celan is extremely critical towards Germany and its role in the war. He even goes so far as to locate the abstract idea of "Death" in Germany. Death is to be found both in the cruelties of men like the camp guard, and also in the ideology of Nazism, with its emphasis on racial "mastery."
his Death is ein Meister aus Deutschland his eye it is blue he shoots you with shot made of lead shoots you level and true a man lives in the house your goldenes Haar Margarete he looses his hounds on us grants us a grave in the air (lines 31-34)
In line 31, "Death" is directly equated with the guard and his blue eyes. This is the moment at which the tension in the poem breaks out into violence, and the guard starts executing the prisoners. The speaker ironically praises his shot as "level and true," as if all that mattered was efficiency. You really get the sense that the guard holds all the cards and has all the power, and the prisoners could not have fought back even if they had wanted to do so.