Adam Milligan

History
Adam Milligan was born in 1990, the son of John Winchester and Kate Milligan. While John raised Adam's half-brothers, he never knew of Adam's existence until the boy was 12, and only met Adam a handful of times. John would take Adam to ball games, teach him to hustle pool, let him drive the famous Impala and in their last meeting together, encourage Adam to talk to his crush.

Unknown to John, the demon Azazel knew of Adam long before John did, going so far as to plan to use the boy to distract John from his mission of finding the yellow-eyed demon who killed his wife and infected his son Sam with demon blood.

His first plan to kill Adam's mom and send Adam to live with John, giving John another mouth to feed and worry about, went awry when the Adam was hit by the car meant for his mother. His body broken, Adam was near death when his family approached Kate with the solution. The Stynes, whom Kate had distanced herself from, were willing to save Adam by replacing his organs and giving him special enhancements. Kate only agreed as a last resort, not realizing how far they'd go.

Adam survived, but his body was now scarred and he now had unwanted extra organs to make him stronger. A furious Kate once again distanced herself from the family. The enhancements would be erased later on when Adam is resurrected by Heaven.

A few years later, Adam begins to realize he's bisexual, something he first opens up about to his father John, who encourages Adam to talk to his crush, Pete. The two begin dating after Pete gives Adam self confidence concerning his scarred body. Azazel, having given up his plans to distract John, forms another idea to use Adam, and dating a guy doesn't fit into those plans.

Azazel has Pete killed, and sends a Succubus to seduce Adam. Over time, Adam begins developing real feelings for her just as they attend the prom together, and end up having sex afterward, resulting in the Succubus getting pregnant as part of Azazel's plan. She leaves Adam a 'Dear John' note instead of killing him and disappearing the next morning, telling Azazel that her baby is already forming.

Azazel's plan was to use the baby (Part Winchester, part Styne, part Succubus, and thanks to his demon blood, part demon) to present his own special Anti-Christ to Lucifer upon his release. Azazel is soon killed by the Winchesters, and the baby hidden as its mother fears its powers, letting it live in a cellar where it can never be released to the world.

A now twice heartbroken Adam tosses himself into his studying for med school. Two years later, ghouls would eat Adam and his mother for revenge against an already dead John Winchester as his half-brothers give him a hunter's funeral.

Unknown to Adam, the Stynes would resurrect his mother, and thanks to orders from the Styne matriarch, would leave Adam dead, instead opting to clone him. The next year, the real Adam would be brought back to life by the angels to use a pawn against his brothers, only to die again when he falls into the Cage while possessed by the Archangel Michael in a fight against Lucifer.

When Samandriel freed Adam from the cage, they trio met up with Ben Braeden. They quickly bonded and were on the road to redemption. When Adam wanted to give his mother a proper burial, the boys soon crossed paths with the Stynes, as well as Adam's clone. After a vicious battle, the Stynes and the clone were dead, but the Styne legacy would live on with Adam's mother Kate, who agreed to head up the Stynes in exchange for leaving Adam and his friends be.

Adam would later learn that another clone was created from his DNA, this one younger and more caring, much to the Styne's chagrin. After selling his soul to save Ben, Adam learned he had a fathered a child before his death, whom Dawn was using to create chaos. With the help of his fellow hunters, Adam killed Dawn and took the boy in, naming him Hunter, vowing to be a better dad than his own father ever was.

Trivia
Adam is bi-sexual, something he first admitted to John Winchester, who encouraged the boy to be who he was, leading to Adam talking to what would become his first boyfriend.