Jacob Nighthorse (or Jacob Blankenship as it was revealed in season 4 he changed his name in the 1990s) is the main antagonist in the Longmire television show and owns a lot of businesses including the Four Arrows Casino. He is active member of the tribal committee, despite the fact that he barely meets the bloods requirement to be considered Cheyenne.
He is one of Walt’s obsessions, first accusing him of killing his wife, and then later Branch, which led him to blaming Nighthorse for a bunch of little things.
Despite this, Nighthorse helped Walt’s daughter Cady become a legal aid for the Cheyenne tribe, and Henry, Walt’s best friend, get his bar back. Also in a surprising move, he provided vital evidence to help exonerate Walt in his civil trial.