Decio Gomes 
In Nomine Patris [EPUB ebook] 

Jullian Bergamo is a missionary priest who performs jobs for the Catholic Church. But he is not a common priest. He is a venator: a member of the Church specially trained to hunt and kill demons. After being transferred from his old community to the small town of Willinghill, Jullian is faced with a unique case: dead people rising from their graves and wandering freely through the city. He soon finds the source of the problem: the Mormo, a terrible demon necromancer that possesses corpses and transforms them into violent undead. Armed with his faith and courage, the young priest confronts one of the most striking cases in his career as a venator: eliminating the Mormo, while trying to survive the hordes of undead that will do everything to devour each piece of his flesh.