Death in the Ashes (Ashes Series #11) by William W. Johnstone
The war against the Night People continues as Ben Raines and his rebel army destroy the favorite living places of the cannibalistic mutants, forcing them into the open. But as they push through the rubble that once was Dallas, Ben is nearly killed by a death squad led by warlord Matt Callahan. Like Ben, Matt was a writer before the Great War; unlike Ben, Matt has turned to outlawing. Now Ben must meet him in hand-to-hand combat to decide the fate of freedom's cause.