Arthur Morgan was born in 1863 to parents Beatrice and Lyle Morgan. A petty criminal and outlaw, his father was arrested for larceny in 1874, when Arthur was 11 years old. At some point during his youth, Arthur met a girl named Mary Gillis and the two were deeply in love. However, Arthur's preference to a life of crime and the prevalent disapproval of Mary's family caused their relationship to fall through. At some point later, Arthur met and slept with a young waitress named Eliza, resulting in her becoming pregnant with their son Isaac. Eliza knew who Arthur was, but accepted whatever support he offered to her and their son. Arthur would visit Eliza and Isaac every few months and stay with them for days at a time. One day, Arthur arrived at their home and saw two crosses outside. Arthur knew immediately that they were both dead, and later learned that they were killed by robbers, all for ten dollars. The incident hardened Arthur ever since and he never truly coped with the pain.