Mary Winchester is the matriarch of the Winchester family and a retired hunter in the TV show Supernatural. She is the daughter of Samuel and Deanna Campbell, the wife of John Winchester, and mother of Dean and Sam Winchester. She was murdered by the demon emperor Azazel exactly six months after Sam was born, which spurred John into hunting to avenge Mary's murder and causing him to raise Sam and Dean into hunters as well.
She was later resurrected after thirty years by the Darkness and reunited with her now grown sons.
After helping the Darkness reconcile with her brother God, the latter promised Dean she'd repay him by giving him back something he wanted. Dean later discovered that the Darkness had resurrected Mary as a thank-you gift.
After her resurrection, Mary reunites with her son Dean and sees the new world after thirty years. Mary is out of place in it but continues to be a hunter with Dean and Sam. She also befriends the angel Castiel who relates to being out of place and she comes to see him as family after he saves her from the reaper Billie.
Mary finds it hard for her to adjust in being in a new era, due to the unbelievable things that have developed. She leaves her sons to find herself and adapt to the new ways of civilization, though she keeps in contact with Dean after he calls her.
Mary joins the Men of Letters who trained her already skilled hunting expertise and help her with adapting to technology. Mary also helps Sam in defeating the Alpha Vampire.
Mary was left stranded with Lucifer in the other universe and wandered the other world facing problems such as crazed hunters or angels attacking her but Lucifer saved her from the threats. However, they were confronted by Michael who promptly defeated Lucifer after learning they were from another reality.
While mastering his powers, Jack searched for other realms to find Mary for her sons as he wanted to rescue her in order to prove he is good. Jack's search led him to find Dreamwalkers, people who can see other worlds and he found the world she was in.
Jack was found by Sam and Dean, who he told of his plans before letting them see the vision of the world Mary was trapped in. Mary was shown in a cage being tortured by spikes stabbing her repeatedly as she called out for help. This display caused her sons to finally learn she was still alive.
After finding a more stronger dreamwalker and bonding their powers to create a rift, Jack was accidentally sent to the world that Mary was in as she was confused by his presence and identity.
In Good Intentions, Mary was taken out of her cage and was placed in a cell before Michael tosses Jack in it. She learns he is the Nephilim that Kelly Kline was carrying who rapidly aged himself and he tells her that her sons sent him to rescue her. She asks about them and is relieved they aren't present in Apocalypse World and she tells Jack to let Michael kill her since they can't allow him to invade Earth but Jack wanted to rescue her. They escaped when they learn the fortress has a spot of weak warding and the two meet the Alternate Bobby and go to his colony.
Mary helps a survivor before she is confronted by Zachariah who overpowers her and demands Jack's location. She insults him and he moves to kill her but Jack returns and kills the angel in front of Mary and Bobby who just arrived. Mary then saw Jack kill three more angels who were coming.
In Bring em' Back Alive it was mentioned by Charlie Bradbury that Mary and Jack have formed a resistance against Michael.
During Funeralia, Mary and Jack see many victories over Michael's forces but mary is concerned about the survivors they are taking in. She has come to see Jack as family and act as a guiding figure to him.
In Beat the Devil, Mary and her group detect intruders and investigate before she reunites with Dean and Castiel while meeting Gabriel. She hugs Dean and asks him about Sam though Dean's facial reaction tells her his fate and she is devastated. When Dean decides to retrieve Sam's body, the camp bell rings and Sam arrives alive and smiles at his mother before she sees him being followed by Lucifer whose arrival shocks her.