Despite his dapper appearance and charming wit, Robert Quarles is a highly unstable and extraordinarily dangerous member of the Tonin crime family. He arrives in Harlan County from Detroit looking for payment on a debt -- and then decides to stay a bit longer when he finds potentially fertile ground for his own illegal empire.He has a tortured and disturbing past -- even predating his adoption by mob boss Theo Tonin, who considers Quarles to be a son. Quarles is a cold-blooded, ruthless killer who takes particular interest in U.S. Deputy Marshal Raylan Givens after the lawman challenges and, worse, embarrasses him.