What is the main conflict in Blood Meridian, or the Evening Redness in the West by Cormac McCarthy?

Blood Meridian follows a teenager, known only as the "kid", as he runs from his home in Tennessee and finds himself in Texas, a member of a renegade unit of the army still intent on fighting the Mexican War. After entering Texas, this unit is ambushed by Indians and massacred. He then joins the Glanton Gang to avoid jail time and finds himself linked with a dark man he has met before, Judge Holden.