Complete Monster: Captain Terrill is the bloodthirsty leader of the Redlegs, a group of pro-Union looters and pillagers who open the film torching the titular character's house to the ground and murdering his family, including his young son. Enlisted as a genuine federal authority by Senator Lane in order to dispose of any holdouts at the end of the Civil War, Terrill exercises his new power by having his Redlegs massacre a group of surrendering Confederates who had been promised amnesty and mortally wounding one of the escaping survivors himself. Terrill begins a ruthless manhunt for Josey Wales across the countryside after he escapes the carnage, with full intent to move onto Texas afterwards and continue killing rebels, coldly remarking that "Doin' right ain't got no end."
Truth in Television: The fighting in Missouri during The American Civil War really was as savage as the film implies, and in more than a few cases was used as an excuse to address old arguments and rivalries that may not have even had anything to do with the causes of the war itself. In fact some parts of the Missouri/Kansas border area still maintain bitter animosity over the war to this day.