Sam Winchester

Why did Sam leave hunting, and why did he come back?

Because he wanted an ordinary life and very nearly had one. Raised on the road by a hunter father, Sam clashed with John again and again and, at nineteen, left for Stanford University after one last argument. When the series opens he is 22, a senior applying to law school, living with his girlfriend Jessica and quietly planning to marry her. Dean turns up because their father has gone missing, and Sam agrees to help look for him.

The pull back is brutal and specific. Jessica is killed by a demon in exactly the way their mother died, and Sam leaves Stanford to hunt the thing responsible. His story keeps returning to the same tension: a hunter better at the work than he wants to be, who keeps trying to step out of it and keeps being drawn back by the people he loves. He is the researcher of the pair, and the one more willing to understand a creature before deciding it has to die.

What is the demon blood about?

It begins in his nursery. When Sam was six months old the demon Azazel came to the house to feed him demon blood, part of a long plan to prepare a body for Lucifer, and their mother died because she walked in on it. The blood gave Sam psychic abilities that the early seasons treat as a frightening mystery, and Azazel turns out to have done the same to other children, all of them meant to fight until one was left standing.

Season 4 makes the blood a choice. Grieving Dean and then keeping secrets from him, Sam lets the demon Ruby persuade him to drink it to grow strong enough to kill Lilith, and he becomes an addict. He does kill her, but her death was the last seal on Lucifer's Cage, so his victory is the thing that sets the Devil free, and season 5 is in large part his attempt to make up for it.

Why is he Lucifer's vessel?

Bloodline and preparation. Through the Winchester and Campbell families Sam shares a line with Cain and Abel, which makes him Lucifer's true vessel, and Azazel's work in the nursery had readied his body for it. At the end of season 5 he lets Lucifer in, then fights his way back to control and drags the Devil, with the archangel Michael, into the Cage to end the Apocalypse. He returns in season 6 without his soul, which is still down there, and spends much of that season as a cold, efficient hunter who cares for nobody, until the soul is put back and he has to live with what his body did without it.

What kind of hunter does he become?

A leader, by the later seasons. Sam carries the Men of Letters inheritance of his father's side, and the brothers make that order's old bunker their home; when the order's British chapter goes to war with America's hunters, it is Sam who leads the fight against it. In season 9 he is possessed by the angel Gadreel without knowing it, and he loses and regains people throughout, but the show increasingly treats him as the steadier brother, the one whose faith, in Dean and eventually in prayer, keeps the family going when Dean's runs out.

He is also the one who keeps the door open to the creatures they hunt. Where Dean tends to see a monster, Sam looks for the person or the reason behind it, and the series gives that instinct room, from purebloods who live on animal hearts to allies like Rowena and even Crowley. It is the same instinct that once sent him to Stanford: a belief that there might be another way to live.

How does his story end?

With the life he wanted, at a price. Dean dies in the final episode and Sam goes on without him: he keeps the Impala, has a family, names his son Dean and dies of old age, and the brothers are reunited in Heaven. It is the ending the first episode promised and then snatched away, an ordinary life after all, and the series lets it be bittersweet rather than happy. Sam gets the normal life, but only once the person who made the hunting life bearable is gone.