World War of the Dead — Eric S. Brown

As World War II rages across Europe, a bombing run awakens an ancient evil. It rises from the depths of darkness to bring Hell itself with it into the world of man. Armies of the dead claw their way out of their graves to eat the flesh of the living. Germany is overrun within days as the plague of the hungry dead spreads around the globe and not even the streets of America are safe. Three men, a SS officer, a German soldier, and an American medic, suddenly discover they are no longer ordinary and that the powers that they now have may be the world's last hope. With the help of an on the run, shot down pilot, they must overcome their personal demons and find a way to stop not only the endless ranks of the dead who are determined to devour all of mankind but also a monster as old as time itself.