The Thurstan Wildblood series1 Devil's Knight

A crusader knight, who has sold his soul to the Devil, seeks salvation in safely transporting a saintly child home to England. An invincible warrior. A living saint. A demonic spirit. A Holy Land fallen into darkness Amid the mayhem of the Third Crusade, a fearsome knight, Thurstan Wildblood, is charged by Richard the Lionheart with escorting one Melinda of Jerusalem, believed to be a living saint, back to England to help justify his war. But others want Melinda, too: the Knights Templar, who would take her to Rome; Saladin's men, who want her dead; and sell-swords and bounty hunters of every ilk. And yet the indomitable knight has reasons of his own to succeed: after a bizarre encounter with a mysterious figure who promised him unmatchable prowess, he increasingly worries that his soul is damned. Wildblood has strayed far from the light, and Melinda may be his only hope for redemption. But even he will be tested by the hardships and horrors on the journey ahead. He thinks he knows evil. But he doesn't. Not yet. A gripping medieval historical adventure perfect for fans of Christian Cameron and David Gilman.