People have a very strange view of fantasy.
The vast majority of people have a blind spot in their understanding of the genre. They think it started with mythology, moved on to King Arthur and Robin Hood, got revived with Tolkien and everything after was a product of J.R.R's vision with the exception of C.S. Lewis. Sometimes, they remember Conan. However, one of the big things George R.R. Martin gets credit for is adding grit and darkness to the genre. Stuff which was always there and Professor Tolkien removed.
The Sword and Sorcery genre is the predecessor to Dark Fantasy. People remember Conan but it's a much wider and diverse collection of stories than one barbarian. There's Elric, Fafhrd and the Grey Mouser, plus countless other heroes who are, in a word, bastards. They live in worlds where antiheroism prevails and the reward for being a noble hero is unknown because none exist. Every city is a Bronze Age Mos Eisley, a wretched hive of scum and villainy. So what does that have to do with The Heresy Within?
This is a return to that sort of uncompromising storytelling. Indeed, Rob J. Hayes manages to one-up the originals in terms of dark and gritty content. This isn't always for the better as the book's casual use of sexual violence as a background element, thankfully never on-camera, was a real turn-off. Those who are squeamish about such things should be cautious because the author frequently references rape and sexual slavery as an element to establishing his world is an utter ****hole. Like George R.R. Martin's Westeros, however, depicting misogyny is not condoning it and I gradually warmed to the way heroine Jezzet Vel'urn dealt with it.
The premise is three ruthless anti-heroes: Blademaster Jezzet, Inquisitor Thanquil Darkheart, and a bandit called the Blackthorn are all individuals struggling to survive on an unnamed demon-haunted Sword and Sorcery world. There's implications this is, like Howard's Hyboria, a "lost age" of our own world but there's knights and churches alongside God-Emperors ruling over city-states.
Each of them has their own wants and needs: Jezzet wants to escape the vengeance of old partner-in-crime Constance (now a warlord's general), Darkheart wants to uncover a conspiracy in the Inquisition, and the Blackthorn wants to get rich. They're all ruthless and jaded with the Blackthorn (real name: Betrim) being outright evil but all three are willing to do whatever is necessary to achieve their goals. There's one shocking moment, involving a witness to a demon summoning, where I actually had to put the book down.
I found the starkness to be refreshing after I got over my initial shock. Betrim's gang may be scumbags but they're honest scumbags. Watching the characters interact, grow, befriend and betray each other is always entertaining. The book is meaty, too, with over four hundred pages of content. You really get a sense of what this world is all about, its politics, and environments by the end. One of the hardest parts of fantasy writing is so much effort has to be devoted to world-building the characterization sometimes suffers but that's not the case here. Everyone just leaps off the page, even if it's to stab you and steal your wallet.
The actual plot is full of twists and turns with the characters' larger goals occasionally being lost. This is not because I lost interest but because everyone has a different agenda which they try and reach by manipulating the others. The characters lie to each other, lie to themselves, and lie to the authorities. This works to the book's benefit as much of it is framed in a series of short-story-esque mini-adventures where they go from one loosely-connected caper to the next. It all comes together in the end but this is the sort of book which can be read in multiple sittings.
I even liked the romance, which is the last thing I expected in a book like this.
Go pick this up and let the author tell you a tale of high adventure. Just keep one hand on your purse and another on your sword at all times.