Played by Adrianne Palicki, Jessica is unaware of any connection that
Jessica Lee Moore (January 24, 1984 - November 2, 2005) was the girlfriend of Sam Winchester, though she never got to know about his family secret. Jessica was killed by Brady on Azazel's orders in order to motivate Sam to return to hunting.
Azazel orders the assassination of Sam's girlfriend Jessica Moore, who was a distraction. Her death prompts Sam to return to hunting. Demons cannot be killed by conventional means so the Winchesters track down the Colt—a mystic gun capable of killing anything—in "Dead Man's Blood".
It turns out Sam's secret was that he had already seen Jess' death in dreams. He knew it was going to happen and did nothing about it. Dean gets back just in time to smash the mirror and get Sam out of the building.
Azazel aka the Yellow-Eyed Demon (Fredric Lehne) was the thing that killed Sam and Dean's mother; he was the thing that stood over Sam's crib and dripped blood into his mouth, turning him into one of his future soldiers; he was the reason the Devil's Gate opened; and he was the reason, ultimately, that Dean sold his ...
Lilith's deception is revealed when she trips and is impaled on a set of deer antlers, but she is unable to kill Sam and Dean due to it not being part of God's plan.
He wishes it didn't happen. Dean is barely holding it together. He doesn't like that Jack is calling Mary's death, “the accident.” But he plays along and says they understand and they forgive Jack.
Someone, or something, has drawn the Winchesters and archangels to a strange device capable of impregnating anything it touches. Sam and Gabriel end up coming into contact with it, and Sam becomes pregnant.
After Veritas revealed that Sam was lying, even under her power, Sam admitted that he let Dean get turned into a vampire as he knew about the cure and that they could turn Dean back.
Sam loses his demon powers, claiming that the force that transported him and Dean onto the plane cleaned him up. He feels tremendous guilt for starting Armageddon and soon learns his acts have revealed a destiny Dean will be the vessel of the Archangel Michael to fight Lucifer.
The Leviathan eventually reveals to Sam that Dean secretly killed Amy, which horrifies him.
On multiple occasions, Dean has shown that - of all the women he has slept with - he truly loves Lisa. Before and during the first few episodes of, season 6, Dean lives with the Braedens for a full year, living an "Apple Pie" life. Dean's nickname for Lisa is "Lis'".
Before dying, John tells Dean, if he can't save Sam, he'll have to kill him, should he become evil.
Dean, though, had no plans to forgive Sam or even hear him out. Dean decided he didn't want to stick around the brother who was being shunned by the rest of the world and abandoned Sam. Dean didn't even consider how he was the first one to break Lucifer's seals and Sam didn't hold it against him back then.
Finally apologizing, Sam tells his brother, “I should've looked for you when you were in purgatory.” Sam never forgave himself for that. But Dean's forgiven him.
Mary Winchester (Samantha Smith)
Targeted by Azazel, retired hunter Mary had the distinction of being the first character to meet her maker. The Yellow-Eyed Demon pinned Mary to the ceiling of baby Sam's room, slit her stomach, and eventually set her ablaze. Mary's gruesome demise forever scarred the Winchesters.
While trying to cope with his impending death and make the best of his final year, Dean begins to start hunting the freed Demons. Meeting a seemingly helpful demon Ruby, Dean learns that he too may become a demon himself if he burns in Hell too long.
Sam has all the advanced abilities of a vampire elder, but he seems to possess even stronger abilities than a typical vampire elder as he is the last elder chosen by the Dark One.
Vampires have very sensitive senses of hearing and smell, that they can use to track their prey; after turning, Sam's hearing was repaired, and his sense of smell was heightened to the point where he could track Mohamed and Vanessa, despite the fact that they had a head start.
Eileen Leahy - Sam's final love (Season 15)
Lydia met Dean Winchester, along with Castiel at a bar. She shared a conversation with the Winchester and then went to her house where the two enjoyed a night together. Unknown to Dean, Lydia was impregnated with his child and in just a couple of hours, Lydia was already nine months pregnant.
Finding that she has been gone for thirty-three years, Mary finally believes that Dean is her son and the two embrace. As the morning came, Dean and Mary say on park bench, with tears in her eyes, Dean begins telling her about John and how he sacrificed his life for Dean and raised he and Sam to be hunters.
Emma was an Amazon conceived by Lydia and Dean during a one-night stand, unbeknownst to the latter. After trying to kill Dean, Sam shot her, killing her instantly.
Not only does Dean die on a routine vampire hunt, passing away slowly in his brother's arms (which coincidentally may be the best scene in the entire final season), but he's briskly whisked away into Heaven solo.