Otis Miller was a legendary gunslinger often associated with the Wild West. The leader of a gang of outlaws called the Otis Miller Boys, Miller reportedly performed the first robbery of a train in 1866, which turned him into an infamous figure and made him the subject of many dime novels.
Otis Miller was eventually shot and killed by another member of his gang, Charlie Tatum, leaving behind three children, one of which being Otis Miller Jr., who was six-years-old at the time. The latter would later be arrested for being the leader of a gang who robbed a train after a confession deemed him guilty. After several months in prison, he was acquitted after the confession was found to have been fabricated.
- His revolver can be found in New Austin after the epilogue. However, Arthur can acquire the revolver through the use of a glitch or exploit.
- His treasure can be recovered without finding both pieces of the map. Simply approaching the spot and the rare weapon icon will appear on the map.
- Miller's name appears on Register Rock, signed with the year 1879.
- Otis Miller had a series of at least 186 penny dreadful novels dedicated to him, three of which can be found in-game.
- A number of details in the game indicate that Miller is based quite directly on Jesse James:
- Both of them have a similar overall status as infamous, iconic outlaws of the Wild West.
- Both have the same folk song dedicated to them, the real-life 19th-century ballad "Jesse James", with only minor variations in the lyrics to account for name differences in the Miller version.
- Both had a brother by the name of Frank.
- Both had a son named after them who was arrested for a train robbery and subsequently acquitted.
- Both were shot and killed by members of their gangs.
- His surname is likely taken from real life outlaws Clell and Edward Miller, members of the James-Younger Gang.