Darkness, book 3 : Through the darkness
Harry Turtledove2001

World War 2 meets epic fantasy... As the war which consumes Dervelai drags on, the reserves of Algarve are ever more stretched. King Mezentio's armies become sucked into the huge landmass of Unkerlant. As more and more of the hated Kaunians are sacrificed for blood magic, conquered races are indected into the Algarvian army, and their fighting edge becomes blunted. While at home, both men and women come to doubt the war and its purposes. Harry Turtledove's blending of World War Two with fantasyhas already gained enormous praise. As a myriad of characters deal with reality, this is a tapestry of the finest writing the genre can create.