John Winchester was a mechanic who existed in the Apocalypse World.
He was the alternate reality version of John Winchester.
Like his counterpart, John was a mechanic who dated Mary Campbell.
In 1973, John was murdered by the Prince of Hell Azazel who offered Mary a deal to resurrect John if Mary gave him permission to enter her home in ten years time. Unlike her Main Universe counterpart, Mary refused the deal and John remained dead.
According to Bobby Singer, Mary never got over the death of John, the love of her life. Mary never moved on from John and never had children by the time of the Apocalypse. In 2017, Bobby relayed this story to the Main Universe version of Mary who had made the deal and as a result, her sons Sam and Dean were able to stop the Apocalypse.
- Because Mary refused Azazel's offer and John stayed dead, his and her future children never existed.