This Forsaken Earth by Paul Kearney
"Nothing moved in all that tangled mass of wreckage and shredded cordage and shattered spars. All along the decks, flesh, wood and iron had been beaten into one unholy, pulped mess from which trickled streams of blood that freshened the brown stains venting from the scuppers. The enemy vessel was a dead thing which even the wind could no longer stir. The Revenants stared around themselves in heavy wonder, as if uncertain as to who could have brought such a thing to pass. A silence fell, broken only by the weary creak and groan of seaborne wood, the death rattle of a tall fighting ship. There was a moment almost of reverence. 'This,' Rol said, 'is victory.'" The Revenant, black ship of Rol Cortishane, has been defending the Hidden City of Ganesh Ka for eight months now. What began as piracy has become full scale warfare, a continual battle to turn back the warships of mighty Bionar. But Ganesh Ka's luck has run dry. Eventually an armada is sent out, against which there can be no hope of victory. The Hidden City is sacked, its inhabitants put to the sword, its ships burned at the docks. The Revenant and a few other vessels escape the slaughter, laden with refugees. Taking to the high seas, they must contend with storm, shipwreck and pursuing fleets in their search for a new home. Not only that, but Rol, their reluctant leader, has begun to realise that in his soul there exists a power which is inimical not only to his shipmates, but to all of mankind. Among the refugees and slaves Rol rescued are an old man and a half-witted boy. The man is the Creator incarnate, the boy His only son. They have come upon the earth to judge mankind, and Rol will finally come to realise that he is one of their tools. He is to become the Angel of Death.