Demons are close to metaphorical in the book. Rather than big flaming monsters, they are lugubrious parasitic presences that cause or possibly just reflect personal vulnerabilities and failings. And only a few people can see them. Indeed, one could practically read the book as though they didn't really exist. The heart of the book is more about getting rid of these personal demons, burying old history, and achieving forgiveness.
Conan it most certainly is not.
The book reminds me of something Terry Pratchett recently quoted in his lecture in favor of assisted suicide:
Contrary to popular belief, fantasy is not about making things up. The world is stuffed full of things. It is almost impossible to invent any more. No, the role of fantasy as defined by G K Chesterton is to take what is normal and everyday and usual and unregarded, and turn it around and show it to the audience from a different direction, so that they look at it once again with new eyes.