The closest thing you'll get is game of thrones unfortunately. I'd love more dark fantasy stuff made into movies or tv series. I'd love to see stuff like Joe Abercrombie, or Mark Lawrence, or Scott Lynch translated to the screen, since Darker Fantasy is like my favourite genre.
If you want to play Demon's Souls for the lore, I'd suggest reading an intro wiki and picking a sorcerer. Seriously, it makes the game about 50 times easier. But, if you're interested, I highly recommend checking out Vaati's videos on Demon's Souls. It's got some weirdly poignant themes about religion vs intellectualism, existentialism, and nihilism that I think are well worth exploring. I'm honestly thinking about writing a blog about how Souls games portray religion, but I'm going to need to do some research for that one.