I'll re-post my mini-review. It's my favourite fantasy series so I'm biased, but yes, they're dark and atmospheric in parts, and certainly can be very horrible and grisly.
After a car knocks him unconscious, leper outcast unclean anti-hero Thomas Covenant finds himself transported to The Land, an imaginative world with such tangible beauty and life that one can't help but care about it as passionately as the characters themselves. Covenant's nerve-ends awaken; his leprosy is fading. In stark contrast to his years as an outcast in his home-town, he is now hailed as a reincarnation of the legendary Berek Halfhand, a saviour of the land. But is it illusion or reality? Should Covenant attempt to save The Land from the deadly Despiser as its legends prophesise, or retain his detached leper mentality to survive should it prove to be the former? This is a tale of sanity, survival and discipline, of struggle and purpose, of love, of redemption, of conquering despair and despite, where the external and internal run parallel with the line between them frequently blurred, and fundamental ethical questions are forced like hot knives into the mind of reader and character alike. "The Chronicles..." are as savage as they are beautiful, with a controversial rape scene forcing many to stop reading after only a few chapters, but ultimately this is a wonderfully imaginative, liberating, entrancing tale - probably the best epic fantasy has ever produced.