I'm not at all a fan of turn-based strategies, I usually find them boring, but Darkest Dungeon didn't just appeal to me, it really sucked me in and is one of my favorite games.
Darkest Dungeon (hereinafter I will call it DD) is one of the most hardcore games I have played, and it is hardcore not only in the composition of tactics, perks, action planning, etc. You are always at risk of losing some hero FOREVER (Well, or there may be an event that will allow you to resurrect the hero from the cemetery, but this is extremely rare), the game always keeps you in suspense not because of the atmosphere, but because of the constant risks. The pain for the player is not only maintaining the physical health of the heroes, but also the moral one. If suddenly one of your heroes experiences psychosis (which reaches at a stress level of 100/200), then he will begin to do crazy things: make moves himself, cancel moves, cripple himself and even others. This drags down not only the hero, but also his comrades.
DD is not just a turn-based strategy - it is the eternal risks and tensions that the game presents in dark, bloody and sometimes grotesque visuals. Even if you're not a strategy fan, give DD a try.