John, better known as The Stepfather, is the main antagonist of Lorelai. An unemployed Afghanistan war veteran, he is a violent, drug-addicted murderer, making a living by selling marijuana to kids at the local high school and regularly spending his time by drinking at the bar. He married Miranda Wood some time after her husband passed away from cancer. He had a daughter with her named Bethany Wood, and gained Laura "Lorelai" Wood as his stepdaughter.
It is revealed over the course of Lorelai that he is not only a psychotic alcoholic, but has murdered unknown numbers of people before the events of Lorelai take place. He had a job at the local Birtwistle & Co. Brick Factory before it was demolished, which he used to support Miranda and her family and gain Miranda's trust and loyalty. It is unknown whether or not he truly cared for the Wood family at one point.
As with all other Parasites, his current nature is The Queen of Maggots' doing, as everything to do with her is meticulously planned so that she'll benefit the most in the end. It's likely that she preyed upon his PTSD after he came back from the war, and any other psychological problems he may have had, to turn him into what he is, with him even confessing at the brick factory that he had murdered unknown amounts of civilians even before the events that had taken place that night.