I have never been much of a reader. I do like adventure stories such as Robert Louis Stevenson and Sir Walter Scot.
One thing which caught my attention is in just about all of Stevenson’s novels, the idea of good and evil in the same person is present. For example “long John Silver”.
One of my favorites is “Quetnin Durward”. I sometimes think I am the only person who has read it.
I went through a Walter Scott phase as a pre-teen. The novels, not the poetry. I never could hack the poetry.
If you like RLS I'm sure you've read "Kidnapped" (Alan Breck is another one of your good/evil characters, though more good I think) but have you read the sequel ("David Balfour" in America, "Catriona" in Britain). A political thriller with asides into Scots folklore. The Lord Advocate Prestongrange is the good/evil character there (Sim Fraser and his mirror image Tod Lapraik being 100 percent evil!) "He was kind to me as any father, yet I ever thought him as false as a cracked bell."