The Apocalypse Exile: The War of the Undead Novel 6 (The Undead World)

From the #1 selling Horror author on Amazon: Peter Meredith- The Apocalypse Exile
  The journey across the zombie-filled country does not get easier for the renegades. The Great Plains, the heart-land of America is now home to vast herds of the undead. These savage hordes sometimes stretch as far as the eye can see. Among them live the Azael--men who have regressed back to the bloody and chaotic roots of our collective ancestors where only the strong or the blood-thirsty survive. 
  These far-flung tribes control the interior of the country, using great armies of zombies to inflict their will upon their neighbors. For the moment they are at peace with the soldiers of Colorado and for the moment they only see in Neil and the Renegades a way to make easy money escorting them across their lands at a steep price. 
  It's a moment that can't last. 
  The specter of death lurks among the group. It haunts them and strikes again and again until its appetite is wetted to a point where it can no longer hide behind the innocent face of Jillybean. What skulks in the depths of her mind is driven by ferocious desires, chief of which is the hunger for death. It's a hunger that will never be satiated not until each and every one of them is dead. 
Betrayal, murder, war--The Apocalypse Exile.