{Background Information}

Samuel William "Sam Winchester,Sammy", is a hunter as well as a Man of Letters, along with his older brother Dean.

Both Sam and Dean are related to the Winchester and Campbell families - a Letters family and a Hunting family respectively. The pair also shares a bloodline with Cain and Abel. Because of this, Sam was predestined to be the true vessel of the fallen archangel Lucifer {whilst Dean was Michael's}. Sam is friends with angel Castiel, Prophet Kevin Tran, the demon Meg and former lover-turned-enemy of demon Ruby. He is also the occasional reluctant ally of demon Crowley and for a time was forced to be an unknowing and unwilling vessel for the angel Gadreel {before expelling him}.

After the demon Azazel killed their mother, Mary, both Sam and Dean were raised in the hunting life by their father John. Sam left the hunting life to pursue a career in law, and most likely would have married his college sweetheart Jessica Moore. At the series' start, Sam was reluctant to start hunting again. When Jessica was killed, he was pushed back into the hunting life. However, he has been repeatedly known to try and back out of hunting in the hope of finally having a normal life.

After Sam's quest to remove the Mark of Cain unleashed the Darkness upon the world, Sam was forced to confront the consequences of his actions. For Sam, the situation worsened when Lucifer manipulated the situation to escape in the vessel of Castiel. Sam was left torn between using Lucifer to help battle the Darkness as Castiel wished and his own traumas and the resulting desire to be rid of the rogue archangel as a result.

Following the reconciliation of the Darkness and God, Sam was abducted by agents of the British Men of Letters and tortured. During this time, Sam faced a surprise reunion with his resurrected mother, the return of Lucifer to evil and the draw of the promises of the British Men of Letters to rid the world of monsters. The situation was further exasperated when Lucifer conceived a Nephilim child before his apparent defeat and return to the Cage. With the British Men of Letters threat growing, Sam was forced into a leadership role to end the threat, but suffered losses while battling Lucifer for control of his child.

With the losses of Crowley and Castiel and with Mary Winchester trapped in the Apocalypse World with Lucifer, Sam struggled to find a way to rescue his mother while dealing with Lucifer's son Jack and Dean's growing depression, aided by Castiel's subsequent resurrection. He was also forced to contend with the threat from the last Prince of Hell Asmodeus. However, after Jack got trapped in Apocalypse World as well, Sam fell into a depression of his own, only lightened when a way was found to rescue Mary and Jack.

With the growing threat of the Apocalypse World Michael, the return of Gabriel and the death of Asmodeus, Sam's focus shifted completely to saving his family and ending the threat of Michael and Lucifer once and for all. After being killed by vampires in Apocalypse World, Sam was resurrected once more by Lucifer and reluctantly forged an alliance with his old enemy in light of the situation. Sam's subsequent decision to purposefully strand Lucifer in Apocalypse World again led to severe consequences when Michael and Lucifer worked together to reach the Main Universe. Though Lucifer was finally killed by Dean with the help of Michael, the victory was short-lived for Sam after he was forced to watch his brother taken over by Michael who was let loose upon the Main Universe in the body of his one true vessel.

Sam is very mentally strong, evidenced by his ability to overpower possession by Lucifer. It has been argued that he is the smarter or more intelligent of the Winchester brothers, although Sam himself would disagree.

Over time, Sam has resigned himself to the hunting lifestyle and has repeatedly sacrificed himself for the greater good, highlighting his selfless nature.