Books like Spook's Dark Assassin

The third chilling installment in the new Spook's legend ...An assassin lurks in the darkness between earth and oblivion - but who are they, and what is their mission? The people of the County live in fear of the beasts bent on bringing the war to their home. How can they possibly hope to survive when their fearsome enemies are fortified with the power of a god? Could the creature that moves in the darkness be the savior the County seeks?