In 1972, the Prince of Hell Azazel managed to make contact with Lucifer from his Cage to ask how to free him and begin the Apocalypse. Lucifer tells him he must do two things: release Lilith from the depths of Hell as she is the only one that can break the 66 Seals and find a very special child. Though unaware of why Lucifer needed these things done, Azazel set out to fulfill his "father's" wishes.
In 1973, Azazel began making deals with prospective parents for his "Special Children", including hunter Mary Winchester. He promised that no one would be harmed if he wasn't interrupted when he entered their houses in ten years. He referred to his need for permission as "red tape". A time-traveling Dean Winchester attempted to stop him from making the deal with his mother, but failed.
In 1983, Azazel visited the Winchester home as promised, but when Mary interrupted him feeding baby Sam Winchester his blood, he pinned her to the celling, sliced her stomach open and then set her and the house on fire. This set John Winchester on a path of vengeance that would last the rest of his life until he makes a deal to save his son's life after a demon attack left him near death.
In 2007, Azazel organized a competition between all of his Special Children to determine who would release his demon army from Hell using the Devil's Gate in Wyoming. The showdown eventually left all but Jake Talley dead and Dean made a deal to resurrect his brother, giving the demons a chance to break the first seal.
Having gotten his "winner", Azazel approached Jake in a dream to get him to agree to open the Devil's Gate by threatening his family. After Jake gets to the railroad tracks that form the boundary that demons can't cross, Azazel appears to him in person and gives him the key to the Devil's Gate: the Colt. After Azazel tells him that the Colt is the one gun that can kill him, Jake nearly shoots Azazel until he is convinced to go along with his plans in exchange for riches.
Entering the cemetery with the Devil's Gate, Jake is confronted by Bobby Singer, Ellen Harvelle and Sam and Dean Winchester who had figured out Azazel's plan thanks to Ash before his murder. Jake is shocked to see Sam as he'd killed him then uses his new mind control powers to force Ellen to point her own gun at her head so that the hunters will drop their weapons. Jake quickly uses the Colt to open the Devil's Gate while Dean and Bobby pull Ellen's gun away from her head before she can shoot herself. After Jake puts the Colt in the lock, Sam shoots him four times from behind, dropping Jake. As Jake pleads for mercy, Sam shoots him three more times, killing him. However, while Dean removes the Colt, it is too late and the Devil's Gate opens, unleashing hundreds of demons upon the world and breaking the devil's trap around the area.
As Sam, Bobby and Ellen work to close the Devil's Gate, Dean realizes the Colt is still loaded with the last bullet and comes face to face with Azazel himself. Azazel disarms Dean and throws him into a tombstone, injuring him slightly. When Sam tries to help Dean, Azazel casually pins him to a tree so he can talk to Dean without interruption. Azazel taunts Dean about his deal to resurrect Sam and implies that Sam didn't return as "100% pure Sam." Telling Dean he couldn't have done it without him, Azazel prepares to kill him with the Colt only for the ghost of John Winchester to emerge from the Devil's Gate and pull Azazel from his vessel. The demon and ghost struggle, but Azazel quickly overpowers John and reenters his body. As Azazel stands up, he is stunned to notice that Dean has retrieved the Colt while he was out of his vessel. Dean shoots Azazel in the heart with the Colt, killing him. Moments later, Ellen and Bobby manage to close the Devil's Gate.
The hunters are stunned to see John there, having escaped from Hell itself to help them. John shares a moment with his sons before disappearing a flash of white light to never be seen again. While their mother has now been avenged, Sam and Dean realize that there is now an army of demons out there that they have to deal with, some possibly worse than Azazel. Dean is also forced to tell Sam the truth about his deal to bring him back to which Sam swears to find a way to break it.
- While Sam and Dean believe they avenged both Jess and their mother by killing Azazel here, its not until they capture the demon Brady that they learn that Jess' killer is still out there.
- Unbeknownst to the Winchesters, they kill one of the four Princes of Hell when they kill Azazel.
- This battle marks the first time one of the Princes of Hell is killed. The Winchesters and their angel friend Castiel would eventually go on to kill Ramiel and Dagon while the archangel Gabriel would eventually kill Asmodeus.