The Veiled War - M. W. McLeod - Bog

When Astero enlisted into the army during World War II, he accepted the dangerous consequences. Little did he know he signed himself up to battle in not just one, but two wars. Humans and magical creatures alike joined the battle, and he finds himself thrust into this new world when the vicious witch Catarina detains him for her own special brand of questioning.
Magdiana wanted to keep her head down, but when a distant family member comes to her for help, she accepts the mission. There is one man who can turn the tides in the war, and they must liberate him at all costs.
The pair find themselves stranded and must make a treacherous journey to civilization, but what awaits them is more fear, death, and duty. It's always one last mission for the greater good, but when their next job sends them into the clutches of a demon and his summoner, the pair know they are headed to their doom. If they can finish the job, they might help turn the tides of the war in their favor, and if they fail, it could all come tumbling down.