The Demons Within - Grimluk, Demon Hunter, #3

Grimluk is an orc with one purpose: hunting demons. An isolated farming town has a demon problem, and Grimluk is on hand to fix it. But this time, things aren't that simple. While Grimluk hunts the demon, a rock crashes from the sky; a rock containing something alien to the world of Arkod. Something oozing and grotesque. Something hungry. Hunter becomes hunted as this new threat pursues Grimluk, all but immune to his bullets.
Worse, the creature's deadly shapeshifting nature means it could be anywhere - or anyone - around him. Despite his efforts to protect his new friends and the rest of the innocent townsfolk, Grimluk learns all too quickly that it'll take more than a quick hand and a strong will to win this fight. For nothing is deadlier than the demons within. Can be read as a standalone. Contains strong language, disturbing imagery, and issues of mental health.