The Living Darkness by T. E. Harden

Fanatical cultists and their dark rituals threaten reluctant hero Cole Parrish's safety...and his sanity. Cole must fight the biggest bout of his amateur MMA career while navigating a perilous case brought to him by a mysterious woman from his past. The events that unfold over the course of a fateful week will define his future, if he survives. The Living Darkness is the first book in the action-packed series The Parrish Chronicles. If you like fast-pace thrillers, heroes with heavy fists, and diabolical villains, then you love this high-voltage series from T. E. Harden.