Dark fantasy tabletop RPG

My current long-running campaign of Deadlands is likely due to end around June. All campaigns I've run so far have been either science fiction or horror western games, so I'm thinking about delving into fantasy roleplaying for the first time. What would be the best system for a slightly dark fantasy game, something akin to maybe Diablo or Berserk in terms of atmosphere? I'm looking for something that's relatively simple to learn, is suited for long campaigns and doesn't require a metric ton of supplements. Darkness doesn't necessarily have to come from a high death rate for player characters.

As for context, I've mostly played Savage Worlds, 40k RPGs and nWoD, so I have absolutely no experience of D&D, Pathfinder or any of that.

If you like Savage Worlds, there are at least a couple of possibilities. Runepunk is steampunk-flavored dark fantasy. Sundered Skies is also dark fantasy, but with an almost Traveller / Firefly like structure to it.

There are others, I'm sure, but I've been out of the Savage Worlds loop for a while.

EDIT: The recently released Lankhmar might do. I haven't read the setting book, but the stories on which it is based have a dark edge.

OpenQuest is a very good entry into the BRP/RuneQuest family of things. Percentile-based, so similar enough to 40k RPGs, easy to run, deadler than D&D without being outright punishing and a free Basic version. Easy enough to upgrade to RuneQuest/Legend if you need something more detailed and deadlier.

You may want to look at Shadow of the Demon Lord. The system is definitely simple. I think that it has a Diablo vibe as far as setting is concerned. There aren't a lot of supplements but there are a ton of short adventures and small supplements.

The only place that it might fail is in the long campaign category. It was designed with short campaigns in mind, for the gamer that doesn't have a lot of time on hand. But I think that pacing advancements is possible.

Shadow of the Demon Lord is a good suggestion.

I might also suggest checking out Symbaroum. It's a recently translated Swedish dark fantasy RPG that uses a pretty elegant system, and has a fairly creepy, dark forest setting. A book of translated adventures that forms a mini-campaign is being released as well [the adventures are out in PDF but a print version is on the way soon].

John

Crimson Blades 2nd edition is an homage to the Elric series from Simon Washburne [Barbarians of Lemuria], but using an OSR influenced 1D6 system

Conspiracy of Shadows Revised is one I've always felt never gets enough attention. The setting is a take on Eastern Europe, and players investigate conspiracies and face off with strange creatures if you want. The system for creating Threats [ie creatures] is pretty simple.

Lamentations of the Flame Princess is a very good dark fantasy game. OK the system is just tweaked oD&D, but the advice, ambience and adventures are very good. You can run the adventures with anything, but the system is actually really easy to learn [it isn't D&D 3.x or Pathfinder], and the core book [minus art], the Referee Book and a couple of adventures are free at the moment. I was nevah a fan of D&D back in the day, but this game has just about converted me to olde skoole D&D.

Could always try my Eternity Realms game. It's a d100 game and is more designed for High Fantasy but the setting is such that you could literally do anything with it. Dark Fantasy is easily possible, and Diablo type gaming lends very easily to it, since that is kind of what I had in mind when designing it.

Check it out here.

What about Warhammer Fantasy? If you ignore the excessively high fantasy elements from the wargame that sometimes slide into the RPG, it is supposedly a dark fantasy game with variable amounts of horror elements.

If that doesn't work for you, when you say Diablo I'm thinking that Earthdawn might work for you. It can handle the "dark" aspects with respect to Horrors, and also does the dungeon-delving and hack 'n' slash thing.