Honestly, a truly ruthless lead is what keeps me coming back to dark fantasy. It's not just about edgy violence; it's the narrative honesty. In a grim world, a protagonist who makes pragmatic, brutal choices feels more authentic than a paladin pretending morality survives in the abyss. Look at Jorg Ancrath from 'Prince of Thorns'. His path isn't glorified; it's horrifyingly logical given his trauma and goals. The story doesn't ask you to like him, just to understand the engine of his will. That complexity, where the line between villain and hero evaporates, is where the genre really digs into human nature.
That ruthlessness also completely warps the power dynamics around him. Allies are tools, loyalties are transactional, and every relationship becomes a potential threat assessment. It creates this constant, low-grade tension where you're never sure if a side character will survive the next chapter or be sacrificed for a percentage point of advantage. The narrative can't rely on found-family warmth or unshakable bonds, so the stakes feel visceral and immediate. You're navigating the story alongside a live wire.
My favorite thing is how it forces the world to react realistically. A ruthless protagonist doesn't get plot armor from the universe being nice; they forge their own from the consequences of their actions, and watching that domino effect is half the thrill.