A Desert Called Peace, by Tom Kratman, paperback science fiction novel
“Five hundred years from now, humankind has found a link to a remarkably Earth-like planet and settled there, dividing as humans will — into dozens of nation-states. The Federated States of Columbia has consolidated power and risen against the oppression of Earth’s corrupt Caliphate. But when Salafi madmen bent on a new jihad kill FSC Captain Patrick Hennessey’s family in a cowardly attack, they create an enemy that will show even less mercy than they do.
A legendary warrior is born: Carrera, the scourge of Salafism. He will forge an army from the decrepit remains of a military in a failing state. He will find those who killed his family. He will destroy them utterly. And he will try like hell to not becoming exactly like the enemy he is fighting. Only when he is finished will there be peace: the peace of an empty wind as it blows across a desert strewn with the bones of Carrera’s enemies.”