Jack Marston

Jack is the only living child of John and Abigail Marston, and the sole surviving member of the Marston family.

In 1906, John was badly wounded in a botched bank robbery. John took this as an opportunity to abandon his life of crime after he was left for dead, as John often puts it. John left with Abigail and Jack, (and assumedly his daughter, who is implied to have still been alive in 1906 as stated by Javier Escuella in The Gates of El Presidio) moving them to a ranch on Beecher's Hope to try and start over as ranchers and give Jack a better life.