Legends of the Red Sun, book 2: City of Ruin
Mark Charan Newton2010

Viliren: a city of sin that is being torn apart from the inside. Hybrid creatures shamble through shadows and barely human gangs fight turf wars for control of the streets. Amidst this chaos, Commander Brynd Adaol, commander of the Night Guard, must plan the defence of Viliren against a race that has broken through from some other realm and already slaughtered hundreds of thousands of the Empire's people. When a Night Guard soldier goes missing, Brynd requests help from the recently arrived Inquisitor Jeryd. He discovers this is not the only disappearance the streets of Viliren. It seems that a serial killer of the most horrific kind is on the loose, taking hundreds of people from their own homes. A killer that cannot possibly be human. The entire population of Viliren must unite to face an impossible surge of violent and unnatural enemies or the city will fall. But how can anyone save a city that is already a ruin?