Blood Meridian

Blood Meridian or the Evening Redness in the West is a 1985 Western novel by American author Cormac McCarthy. McCarthy's fifth book, it was published by Random House.
The narrative follows a teenage runaway referred to only as "the kid", with the bulk of the text devoted to his experiences with the Glanton gang, a historical group of scalp hunters who massacred Indians and others in the United States–Mexico borderlands in 1849 and 1850. The role of antagonist is gradually filled by Judge Holden, a large, intelligent man depicted as entirely devoid of body hair and emblematic of violence and conflict.

Blood Meridian by Cormac McCarthy

The men as they rode turned black in the sun from the blood on their clothes and their faces and then paled slowly in the rising dust until they assumed once more the color of the land through which they passed." If what we call "horror" can be seen as including any literature that has dark, horrific subject matter, then Blood Meridian is, in this reviewer's estimation, the best horror novel ever written.