Luthor cuts his mate's wrist and she force feeds it to the woman, kissing her with the blood in her mouth. “Welcome home, baby,” Luthor says. That woman, now vampire, is Jenny – who returns 15 years later in Supernatural's series finale as the leader of the nest of vampires who kill Dean Winchester.
A short time later, Dean remained suspicious of Sam letting him be turned into a vampire. 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.
Before dying, John tells Dean, if he can't save Sam, he'll have to kill him, should he become evil. The fourth season episode "On the Head of a Pin" reveals that the demon Alastair tortured John in Hell for over a century, with John refusing the demon's offer to stop if he himself would torture someone else.
In a future God shows Sam where the Winchesters and Castiel succeed in locking God away, Sam is eventually turned into a vampire on a hunt gone wrong. During a final confrontation with several hunters, including both Jody Mills and Bobby Singer, Sam is shot in the chest by Jody with a dead man's blood bullet.
Boris later sees Dean in an alley and, after telling him he's pretty, he attacks and feeds him his blood, turning Dean into a vampire.
Season 3. 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.
Dean later briefly possessed a pair of Black Eyes while he was a Demon. Since separating from Sam, his appearance has become more scruffy and unshaven; his hair has also grown out a bit. In Let the Good Times Roll, Dean gains a pair of Angel's Wings due to his status as Apocalypse World Michael's current vessel.
By drinking demon blood Sam's power become stronger, to the point where he can outright kill demons and even torture them while in their human hosts; by drinking at least three gallons of demon blood, he can kill demons just by concentrating and willing it to happen.
Sam is pregnant with Dean's triplet sons. Although he is only 7 months his belly looks like he is about to pop. Sam has a hard time moving around with the weight in his belly and is almost stuck in the bed till he gives birth.
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.
Emma Winchester is the daughter of Dean Winchester and Lydia.
Instead of telling Sam the truth about how he'd lost his soul and had hunted without it for more than a year, Dean just told him everything was fine. Sam later discovered not only that he'd done horrible things while soulless, but that he'd gone through some serious torture in hell.
I love you so much. My baby brother.” He then makes Sam promise that it'll be OK, so Sam lays his hand over Dean's and says, “It's OK. You can go now.” “Goodbye, Sam” are Dean's final words as his hand drops and a tear rolls down his cheek.
After all, despite his intentions, Sam did the unthinkable. He betrayed him for a demon. Dean tried to see past it and focus on task but the hurt was too deep and the betrayal too raw. He couldn't forgive.
After Dean died in the series finale, Sam went on to get married and have a child, whom he named after his brother.
After Dean accepts the Mark of Cain from Cain himself in Season 9, it begins changing him, granting him supernatural powers, ramping up his bloodlust, and making him addicted to using the First Blade. The Mark then resurrects him as a demon when he is killed by Metatron in 9.23 Do You Believe in Miracles?.
Eileen Leahy - Sam's final love (Season 15)
That is until Chuck wiped everyone from existence (“Despair”).
Lydia is an Amazon who hooked up with Dean Winchester at a bar and the two made love in bed. She was impregnated by the older Winchester and in just a few hours, she was pregnant with her unborn child.
Kelly Kline was an aide to President Jefferson Rooney. At some point in time, the two began an intimate relationship after the death of Rooney's wife. After Rooney is possessed by Lucifer, she becomes pregnant with his child – a Nephilim named Jack.
Power: Dean
Even if Sam is taller and generally seems more fit, Dean has demonstrated on many occasions that he's the more powerful of the Winchester brothers. No matter if it's a fistfight, a weapons-laden war or simply leveraging his weaknesses against an opponent's, Dean is the better brother.
The episode "On the Head of a Pin" reveals that she is feeding Sam her demonic blood to boost his powers, and by "The Rapture", he has become addicted to drinking her blood.
Grace Removal - When Metatron removed his grace, Castiel gained a soul and became a human, losing all his powers in the process.
Eventually the two comforted each other and slept together, not realizing in a few short months, Meg would be carrying a Nephalem, their unborn child, Cassandra Master. Castiel learned of Meg's pregnancy and did everything in his power to hide her from angels or demons.
While Sam, Metatron and Donatello rescue Lucifer from Amara's hideout, Dean tries to distract her. Eventually, she discovers Dean has met God and that they're planning on freeing Lucifer from her. Metatron stays behind and tries to hold back Amara but she's too powerful for his cast and he is imploded into nothingness.