Adam Millagan is the younger half-brother of Sam and Dean Winchester the son of Kate Millagan, the son to John Winchester and the step-son of Mary Winchester in the CW's hit-tv series Supernatural. He was killed by a Ghoul but was resurrected by angels to serve as a vessel for Michael but this turned out to be a ploy to convince Dean to con. He was played by Jake Abel.
Personality
Adam is described as the polar opposite of Sam and Dean Winchester, As comparing him to Dean is that He loves liquor, music, women and hamburgers along with starting fights with older people.
Comparing Adam to Sam is much more different but the two are similar in certain topics such as having a complicated relationship with their father and questions Dean's actions.
While he was slow to connect with his half-brothers even telling them they are not his family, he came to trust them to a certain extent when he was skeptical of Zachariah's intentions. He was also touched when both came to rescue him after he saw they were right about Zachariah and called him family.
Biography
Adam Millagan was the estranged son of John Winchester who met Adam's mother Kate when he was injured and being a nurse she tended to him. The two formed a relationship before John left town unaware that she was pregnant with their son.
When Adam was twelve he begged his mother to contact John to which she did. After learning of Adam, John headed back to Kate and met his son who he decided to connect with. It was speculated by Dean that John saw Adam as a chance to raise a son in a normal way instead putting him in the dangerous path of a hunter. Also, the time John found about Adam goes along with the time frame Sam decided to attend college, leaving him and his older brother Dean alone. This means he wanted Adam to fill in the role of the son who he can be fatherly to.
John would have many meetings with Adam in the future; taking him to baseball games, teaching him how to drive and giving him a beer on his fifteenth birthday. Despite John trying to be a father to him, Adam never saw him as such and only viewed his mother Kate Millagan as his family. Also, John never told Sam and Dean about Adam while Adam was never informed of John's previous life.
However, being John Winchester's son brought about suffering to both Adam and Kate that causes both to die at the hands of ghouls who wanting revenge on John. Adam was killed by the monsters with one of them taking on his form and the other taking his mother's form.
When this fake Adam first appeared in the series, he met Sam and Dean who were surprised to learn they had a half-brother. This Adam lured them to the house and tricked them in its plot to kill them as the ghouls were children of another ghoul John killed. Since John was already dead, his children had to pay the price of his sin with the Kate ghoul confirming to Sam that Adam was indeed the Winchester's brother.
Sam and Dean killed the ghouls before finding the real Adam's body and giving it a hunter's funeral out of respect for the brother they never knew.
Eventually in Season 5, the angels resurrected Adam from the dead as part of their "plan". Adam is found by Castiel who takes him to his brothers Sam and Dean. Adam then formally meets his siblings but he knew who they were as the angels told him and how they needed him alive for their "Plan" to kill Lucifer, reignite the Apocalyspe and allow Michael (the Greatest and most powerful Archangel of all of God's Children) to possess him.
Adam insists that if he consents he'll see his mother again as he disagrees with their words that Michael is lying as he knows that the fight with Lucifer will possibly deep-fry the planet along with the angels. Adam is distant to Sam and Dean stating they are not his family and he will see his mother again before they get him to at least give them time.
Adam later tries to sneak out but Sam finds him and they talk with Adam once again giving him the cold shoulder and using their father as a trump card. Zachariah later appears to Adam in a dream to get him to side with him but Adam shows he gained some form of faith in his brothers as he is distrustful of the latter's intentions. Zachariah uses Adam's mother as leverage causing him to leave with the angel.
While waiting on Michael, Adam dines on burgers which causes Zachariah to remark he shares the same tastes in food as Dean. Adam inquires as to where the Arch angel was before Zachariah reveals that everything was a lie to lure in Dean as he knew the Winchesters would come to save him. Realizing his brothers were right, Adam protests as Zachariah tells him he'll get his mother back but Adam doesn't believe so Zachariah tortures him to silence him.
Adam lays on the ground in pain when Dean comes to rescue him as Adam was very shocked that he came despite his treatment. Dean replies by calling him family while Adam tries to warn of the trap but it is too late as Zachariah appeared and even subdued Sam after he sneaks up on him.