|Dates||???? - 2017 (killed by Castiel)|
|Location||Rocky Mountain National Park, Colorado|
|Episode(s)|| 11.02 Form and Void|
11.10 The Devil in the Details
11.17 Red Meat
11.23 Alpha and Omega
12.06 Celebrating the Life of Asa Fox
12.09 First Blood
You and Dean... Dying and coming back again and again. The old Death thought it was funny. But now there's one hard, fast rule in this universe. What lives... dies. So the next time you or your brother bite it, well, you're not going to Heaven... or Hell. One of us -- and, Lord, I hope it's me -- we're gonna make a mistake and toss you out into the Empty. And nothing comes back from that. I know you're dying. I can feel it. You're unclean in the biblical sense. So I'll be seeing you again, Sam... Seeing you real soon. Name's Billie, by the way.
– Billie, 11.02 Form and Void
Billie was a reaper who was collecting souls in Superior, Nebraska after the Darkness was released. After the death of Death, Billie made it her mission to ensure that once Sam and Dean Winchester die, they remain dead, threatening to take their souls to the Empty to ensure it.
As Sam is researching possible ways to cure the sickness that came with the Darkness, the song "O Death" begins reverberating through the hospital halls. When he goes to investigate he finds a woman singing the song crouched over a dead body. Sam surmises she is a reaper, and asks her name for which she is not forthcoming. Sam then apologizes for his hand in killing Death. Billie tells him she is sorry too, but that people are still dying and souls need collecting, but also that she is "here" to deliver a message to Sam. All the times Sam and Dean have been coming back to life, ends now. And that the next time they die, they won't be going to Heaven or Hell, but that whichever reaper comes to collect their souls will throw them into the Empty, a place where nothing can come back from. She tells Sam she can feel that he is dying and that he is "unclean in the biblical sense," she then departs telling Sam she will be seeing him real soon, revealing her name to him before disappearing.
When Dean finds out Sam is in Hell with Lucifer, Crowley sends him to Kenesaw, Nebraska where in a derelict looking building he finds Billie standing behind the door. Billie demands the password from Dean and after some protest, he acquiesces to her demand and sings "Camptown Races." Dean initially assumes Billie to be a demon, but is corrected by her. She tells him she is working with Crowley and not for him, citing the state of things currently, that is a good idea to have the King of Hell owe you a favor. She hands Dean and large wooden box and walks over to a pair of doors with sigils painted over them, she touches them causing them to glow and opens the door, which reveals a stairway to Hell. As Dean begins walking down, Billie stays behind and closes the doors.
Sometime later, Billie is sitting around reading a comic book when Castiel suddenly appears before her. She nonchalantly greets him and gives him access to Hell.
Desperate to bring Sam back to life, Dean overdoses on a handful of pills in order to get a face to face with Billie. Once out of his body, Billie emerges from a white light and freezes the room, telling Dean she is savoring his death. Billie quickly realizes that Dean is too much of a martyr to commit suicide, and asks him what he wants from her. He tells her he needs Sam back, Billie looks at Dean confused, but Dean continues to make a deal which Billie coldly passes on. Dean appeals to Billie by telling her the Darkness is still free, and Sam can stop her. But, once she gets started the world will burn, destroying everything and everyone including Billie. When Billie questions Dean how Sam can stop, Dean can't answer. Billie applauds Dean for pretending to want to save Sam for the "greater good," but sees right through Dean and knows he's doing it for himself, because he can't lose Sam. Billie tells Dean that even if Sam could stop the Darkness, the answer would still be "no," as the Winchesters have lost all their second chances. When Dean attempts to trade his life for Sam's, Billie once again refuses, telling Dean she is here to reap him, not bargain and remarks on the irony that Sam is not dead, but Dean soon will be. Billie extends her hand and tells Dean his time is up and that the Empty is waiting for him. As Dean stares blankly at Billie, Dr. Kessler injects a syringe of adrenaline in his heart reviving Dean, prompting a dismayed Billie to walk out of the room and into the white light from where she came.
After Sam and Dean collect the ghosts that have resided at Waverly Hills Sanatorium, Billie appears, watching the Winchesters walk away. Later when Sam and Dean return to the Bunker, the security system seemingly shuts down as Billie makes her entrance. She tells Sam and Dean she saw them at Waverly Hills and questions why, with the world coming to an end, they would be out "busting ghosts." They tell of their plan to collect souls for a bomb to kill the Darkness. To which Billie simply replies with an "okay" and offers to help them. With the crystal in her hand, souls begin whooshing into the Bunker to it in increasing volume. When asked how many she collected, Billie tells them a couple hundred thousand, having raided the souls stuck in the Veil.
Billie appears outside of the house of dead hunter Asa Fox and tells Dean that something is killing hunters inside and she had already reaped a soul within. Billie is amused by Dean's efforts to get in and agrees to get him inside in exchange for him owing her one. Billie is able to throw Dean through the warded door and into the house. The next morning, Billie appears and tells Dean he owes her one: Mary Winchester. Billie tells them she's a believer in that what's dead should stay dead and states that she can tell that Mary doesn't want to be alive and offers her mercy by taking her to Heaven. After Billie confirms that she can't kill Mary due to the rules, Mary declines and Billie tells the Winchesters that if any of them ever change their mind, to call her and Billie disappears.
A desperate Dean calls Billie for help for escaping from Site 94. Billie makes a deal bound in blood with the Winchesters where she will kill them for a time and then bring them back to give them a chance to escape. In return, one Winchester must die for good at midnight. At midnight, Billie appears in the road, stops Mary's car, explains the deal and demands the Winchesters keep up their end of the deal. Mary offers herself up in her sons' place and goes to take her own life, but before she can, Castiel stabs Billie from behind with an angel blade, killing her and stating that the world can't afford to lose any of the Winchesters.