Clone of D&D suited for Dark Fantasy?

I'm looking for a "almost clone" of D&D that gathers all of its rules in a single book of easily digestible size (200-300 Pages maximum) instead of the three books. I don't care which version D&D is cloned, what I'm looking for is a RPG that would allow me to emulate a universe inspired by the Black Company or Berserk,gritty, humans only and Dark and low-fantasy. If I go on a "D&D clone" instead of the usual answers like Warhammer it's because in these kind of games the PCs are as powerful as anemic mushrooms, without going into a Shonen Fantasy delirium I would like the PCs to be powerful enough to have the opportunity to shine and "be cool".

I already know that Black Company for D&D 3.5 is already a thing but I also think that 3.5 sucks ass, so it's out.

Also, no Narrative Game, no PBTA games, No blades in the dark variant and such other similar concepts, thanks but no thanks.

Our very own ColeMaibara has published a few third-party supplements for Pathfinder under the label of Black Flame Studios, check those out!

Symbaroum. Unfortunately, it is quite tied to the setting it comes from — but I believe this can be circumvented if you want to adapt it for a magicless setting. The race system is also used for different cultures, and each race is a maximum of two or three different traits each, and it can be really easily homebrewed to work as cultural background (as Symbaroum does between Ambria humans and barbarian humans) or backgrounds (like giving your gladiator players a trait that makes them better with swords).

Alternatively, try a generic system like GURPS or FATE.