RPGMemes

Thematically this is just a tone to set for running an RPG, but system wise...

If sticking to Sword and Sorcery...

I want the consequences to be so real that a decent player might need 2 or 3 backup characters, where a happy ending isn't garunteed in the slightest and the DM is fine to end the campaign in total tragedy.

...You might like Dungeon Crawl Classics. Uses funky dice (optional), and you start with a few "level zero" characters that go through a deadly dungeon known as a "funnel." The survivors end up as your level 1 character(s).

Maybe thematically it's not about pull-no-punches storytelling or anything, but the system itself is brutal and rewards player cunning, wit, and luck, to overcome challenges. (And no, the DM isn't required to be an adversarial psycho lol.)

Never played it myself but it falls into that category of "OSR" kinda games that try to revitalize the spirit of classic "Player smarts vs. Consequences" gameplay over theatrical plot-beats.

Apart from fantasy, my favorite system is Savage Worlds. It can run any genre, the game by default is "cinematic" and favors the players as heroes, but many mechanics make the numbers "swingy" so nothing is ever "not dangerous." With the right rolls, a squire can behead the Orc war chief, or a lowly thug's .38 caliber could put your spec-ops commando in critical condition!

It's also heavily customizable. You want pulp adventures where heroes shrug off bullet wounds with sheer grit? Easy!

You want what you described up there where every victory is won tooth and nail? Try adding an optional rule where every wound causes a potentially permanent injury in a setting like "War of the Dead" or "Weird Wars Rome / I / II / Vietnam" and things are gonna get real tense, real quick.

Players have lots of tools at their disposal, but dice also "explode" both ways. Sometimes an inconsequential attack can one-shot you into bleeding out, but I guarantee the whole table erupts when a player goes for broke and the dice just keep poppin'! Love that system.

It's very quick and easy for GMs to run too, I'd say. Great balance between narrative flexibility and tactical "crunch." :)