how did the main characters emotions change through the war?

All of the boys become bitter and dejected young men. Each character changes in their own way. Detering can't handle being away from the farm. He can't stand hearing the suffering of animals like the horses who die slow and painfully in the field. He ends up going AWAL but is caught. All the men dream of peacetime in their own way but there is always a sense of fatalism to their discussions. They have seen too many boys and men die to believe they will get out alive. They become forlorn and isolated. Unlike the older men, they have not experienced life yet. They are virgins (most of them) with rifles. They increasingly become distant from their own families and hang onto each other. Paul watches nearly all of his comrades (Kemmerich, Müller, Kropp, Kat, Bertinck) disappear one by one. By the end there is nearly nothing left for Paul until a shot in the head gives him his final release.