Blood Meridian has a dark, violent, and desperate mood. The novel is in many ways a bildungsroman—a coming-of-age story—that charts the life of the kid, reflecting on his birth at the start of Chapter 1 and ending with his death at the hands of the Judge.
The kid becomes a man through violence, with his untimely death appearing somewhat inevitable and contributing to the fatalistic mood of the story. The kid's journey to manhood is as implausible as it is violence-filled, and McCarthy often deliberately chooses to dwell on the most visceral elements of the most violent acts. The harsh nature of the desert landscape sucks the life out of the characters in it, and the reader is often likewise exhausted by being immersed in that landscape, as McCarthy's prose lengthens accordingly.
The novel is filled with religious allusions, which further contribute to the mood: not only are the trials and tribulations that shape the kid into a man centered on violence, but as the Judge proclaims, "war is god." What motivates many of the characters in the novel, the scalp trade, is a monetization of brutality which permeates the story with a melancholic resignation to violence as a way of life.