The Blind Owl by Sadegh Hedayat
The Blind Owl is unsettling and darkly romantic. It's an Iranian classic and I only ran into it because I was looking for something by a South Asian writer, but it's definitely worth reading.
The book has two distinct parts. The first one feels almost like a nightmare, but a calm one. It has an inevitability but not one that makes you scream. I chose not to use the word nightmare because no matter how macabre this first part is, it has a peaceful almost tranquil quality to it. Our narrator sees a beautiful woman who he falls in love, or at least lust, with. Then, he ends up killing her and the section becomes more and more disturbing.
Then we have a break. The second part presents an alternative story, maybe more realistic but our narrator is still not fully connected with reality. He tells us about his complicated family history and about how he is in love...