|Powers||Can kill most demons and hellhounds.|
|Location/Owners||Currently in Sam and Dean's possession.|
|Episodes|| First Appearance: 3.01 The Magnificent Seven|
Last Appearance: 9.17 Mother's Little Helper
This knife originally belonged to Ruby and is capable of destroying most demons (albeit at the cost of killing their human hosts at the same time). Its blade is inscribed with symbols and the handle is wood or bone. Of all the demons that have been stabbed with the knife, only Alastair,Abaddon, and Cain  have been shown to be immune to its killing power. Sam noted at one point that Lilith was also scared of it, but she may simply have wished to avoid the pain rather than being actually vulnerable to the knife's power, or was unaware of the effect it would have on her. Bobby was able to survive stabbing himself with it while he was possessed, but the knife left him paralyzed from the waist down, and it was unclear if this killed the demon possessing him or merely forced it to retreat. It also has no effect on angels, but it can kill hellhounds.
Ruby appears during the battle with the Seven Deadly Sins, and kills three of the demons with a knife. Until this point, the only ways of getting rid of a demon had been exorcism, which sent it back to Hell, or with the Colt, which killed it. Bobby states that he has never heard of a blade that could kill demons.
Dean steals the knife in the hope of using it against Lilith, and kills a possessed policeman with it after seeing his true demonic face as well as using it to kill a few demons protecting Lilith. However, when Sam attacks her with it, she stops him with her powers. Later, after Dean has been killed, Sam is able to withstand her power, and she vacates the body she is using to escape Sam's attack with the knife.
When Dean learns that Sam has been using his powers from Azazel to exorcise demons, Sam justifies the decision by arguing that this method saves the host, arguing that the knife kills the victim as well as the demon. Also, upon realizing that the girl with Sam is Ruby, Dean attacks her with the knife, but Sam stops him from killing her.
When facing Samhain, Dean demands that Sam use the knife rather than his powers over his objections that Samhain might be too powerful for the knife alone to do the trick. Despite this, Sam does try to use the knife, but loses it in the fight and is forced to use his powers to exorcise Samhain instead.
Sam stabs Alastair with the knife, but it appears to have no effect on him. While escaping from Alastair they lose the knife. In flashbacks, Ruby is shown taking the knife back from Sam and killing the demon with her with it and then later killing a demon after Sam fails to exorcise it. They use it in the fight when they walk into Lilith's trap.
Alastair uses the knife to torture Ruby. He says to her "This knife of yours... It's an exquisite piece. You must tell me where you found it." When Alastair’s meatsuit is destroyed by Anna regaining her grace, the knife is left behind unharmed, allowing Sam and Dean to retrieve it.
Dean uses the knife to torture Alastair (now using a new meatsuit) who later beats Dean unconscious after being freed from the devil's trap. Castiel arrives and throws the demon-killing knife into his shoulder. Castiel twists the knife with his powers, but Alastair manages to pull it out and lunges at the angel. Alastair attempts to send Castiel back to Heaven, but is interrupted by Sam.
Dean uses the knife to kill a demon possessing one of the Novak family neighbors. Later, when the demons capture them, they get the knife as well, but Sam gets it back in the fight that follows, cuts the neck of one of the demons to drink her blood, then kills her with the knife before using his powers to exorcise Amelia Novak.
Castiel uses the knife to cut his arm so that he can use his blood to draw the angel banishing sigil and temporarily get rid of Zachariah. Castiel gives the knife to Dean before sending him to St. Mary's Convent to stop Sam from killing Lilith. Dean is unable to prevent the last of the 66 Seals, Lilith's death, from being broken. He instead attacks Ruby, who is revealed to be working with Lilith with the knife. As Sam holds her in place from behind, Dean stabs Ruby with her own knife, killing her.
Meg orders the possessed Bobby to kill Dean with Ruby's knife, but just as he is about to strike, Bobby manages to wrestle control and stab himself in the abdomen instead, killing the demon possessing him. The stab wound Bobby inflicted on himself with Ruby's knife led to his inability to walk. During the fight that follows, Dean manages to grab the knife and kill another demon causing Meg to flee before he can stab her too.
When Sam and Dean go after War and cut off his ring, they take the knife to use against him. He comments that it can't kill him, but they use it to cut off his fingers instead and disable his powers by removing his ring.
Dean carries the knife while visiting Jesse Turner's house to find out what is causing so much trouble in town. Later, Castiel tries to kill Jesse with the knife, but gets turned into an action figure of himself holding the knife.
Sam uses the knife to try to kill Crowley - and slices into the Impala's rear seat when the demon disappears. He makes another attempt, but is again unsuccessful. Later, Dean takes the knife and uses it to kill a demon protecting Brady. Sam eventually uses the knife to kill Brady.
After trapping Crowley under a devil's trap, Meg tortures him to find out if he can restore Sam's soul. When he denies he can, Dean hands the knife to her so she can kill Crowley, but he overpowers her and uses the knife to break the devil's trap. Castiel then appears with Crowley's bones, which he burns to kill Crowley. Seizing the moment as a distraction, Meg escapes before Dean can kill her.
Dean has the knife when he confronts Guy, the crossroads demon. He loses it in the fight, and Becky uses it to kill Jackson. Dean then uses it to overpower Guy, but before he can kill him, Crowley arrives and makes a deal instead.
Dean and Sam surprise Jeffrey, and hold the knife to his throat while they use holy water to see if he is a demon. Jeffrey later uses it as part of his ritual to cut Dean and get his blood and to kill his dog for her heart. Later, after Sam lures the demon into a devil's trap, Jeffrey tries to attack the demon with the knife, forcing Dean to kill him.
Dean encounters a demon at Emmanuel's house and uses the knife to kill him. Later, Dean is confronted by three demons at a convenience store and he manages to kill one with it but loses the knife. However, Meg picks it up and kills another one and the last demon flees as a result. Later, when discussing all the demons outside the Northern Indiana State Hospital, Castiel/Emmanuel asks if they have more knives to fight the demons with, but Dean tells him all they have is one.
Meg steals the knife and uses it to kill Rosco and another demon. However, Sam and Dean are aware that she left and she walks straight into a devil's trap upon return and is forced to hand the knife back over. However, Castiel is able to confirm her story about killing two other demons as he can smell demon blood on the knife.
When the devil's trap in the church Kevin Tran is hiding out in is broken, Sam and Dean realize that demons are coming and Dean hands Sam the knife to fight while he uses a blade he got in Purgatory. With the help of Kevin, Sam kills one demon with the knife then tosses it to Dean who kills the second attacking demon with it. Crowley then shows up and Dean faces off against him with the knife, but when Dean tries to use it on him, Crowley causes it to burn Dean's hand, forcing him to drop it though Dean is able to quickly pick it up again.
While checking on Linda Tran, Sam and Dean discover two demons watching her, one possessing a gardener and the other a mailman. Dean lures the gardener away from the front of the house and kills him with the knife and Sam does the same with the mailman. Later, when they find that Linda's friend Eunice is possessed by a demon too, Dean uses the knife to kill her after Sam forces the demon back into her body with a reverse exorcism.
After arriving at Plutus' auction, Dean is forced to give up the knife, but promises to get it back. During the struggle that later follows, Dean spots the knife and grabs it to go after Crowley who is possessing Mrs. Tran. Dean fights Crowley and tries to slit his/her throat, but he flees Mrs. Tran before he can.
After finding out that Linda Tran has captured a demon, Dean pulls the knife on the demon, presumably to torture information on the location of Kevin Tran out of it. The demon gives him the location and after arriving there, Dean kills the demon with the knife. While making his way into the warehouse the demon led them to with Sam and Castiel, Dean used the knife to kill a demon that was guarding the building. Dean later tries to kill another demon with it, but is telekinetically thrown into a mass a chains and Castiel is forced to kill the demon with his powers, which weakens him.
During the attack, Dean kills a demon from behind that is strangling Sam. After finding Samandiriel, Dean fights Viggo armed with the knife. Dean ultimately overpowers the demon, but after seeing an opening, kills the demon Sam's fighting instead. Viggo pleads for his life, claiming he knows things they need to know, but Dean, after pretending to agree, stabs him with Ruby's knife, killing him.
When facing the demon Abaddon, Dean stabs her in the back with the knife, but while it hurts her, like with Alastair it doesn't kill her. However, the distraction allows Sam, Dean and their grandfather Henry Winchester to escape.
When Sam and Dean wonder why the knife didn't work, Henry tells them that normal knives wouldn't and that they would need an "ancient demon-killing knife of the Kurds." When Dean shows him the knife, Henry is surprised and asks where they got one and Dean tells him from a demon. Presumably the knife didn't work as Abaddon is a Knight of Hell and one of the first demons ever created.
When going after a hellhound in order to kill it as part of the three trials needed to be completed to close the Gates of Hell, Dean shows Sam the knife when describing how they will kill the hellhound.
When Dean finally confronts the hellhound, he loses the knife and the glasses that allow him to see it, but Sam manages to grab the knife and cut the hellhound open lengthwise, killing it and completing the first trial.
When Dean, Sam, Meg and Castiel go to Lucifer's Crypt to find the angel tablet, Dean gives Sam the knife and tells him to wait outside with Meg and guard the building. Two demons attack and Sam kills one with the knife while Meg kills the other one with an angel sword.
In Hell, after finding Bobby, Sam gives Bobby the knife to defend himself with while he uses the vampire's weapon. Bobby kills two demons with it and when confronted with two Sam's, makes a guess and stabs one, luckily killing the right demon one.
Back in Purgatory, when Sam is preparing to escape through the portal out with Bobby and Benny Lafitte, Sam uses the knife to cut his and Bobby's arms so he can absorb Bobby's soul for the ride out. He offers the knife to Benny to do the same, but a group of vampires arrive and Benny, who had no intention of returning to Earth at all, stays behind to hold them off.
On Earth, Sam uses the knife to slice open his arm again and recite a spell to release Bobby's soul to Heaven, ultimately succeeding thanks to the aid of Naomi. When Crowley shows up, Sam tries to attack him with the knife, but Crowley pins him and Dean to trees instead.
While working on curing Crowley of being a demon, Sam has the knife with him. He uses it to cut himself when he performs the exorcism that will finish the job, but Dean stops him before he can put his hand over Crowley's mouth with the blood and finish the job.Abaddon and the demons loyal to her, Sam arms himself with the knife, but is overpowered by three demons. However, Gadreel takes control after Sam is knocked out, overpowers the demons and kills them with the knife rather than his powers so Dean can explain away their deaths to Sam without Gadreel having to reveal his presence to him.
When Crowley shows up at the bar Dean is at, he pulls the knife on him and keeps it out while they talk, but eventually puts it away after Crowley convinces Dean to work with him to locate the First Blade.
When four demons attack Cain's house, Dean takes on three with the knife while Crowley kills the last with an angel sword. Despite an intense fight in which Dean briefly loses the knife to one of the demons, he manages to kill all three single-handedly, proving himself to Cain to be worthy of the Mark of Cain. When Cain refuses to give Dean the First Blade, Dean threatens him with the knife, but Cain merely stabs himself with it, proving to be completely immune to the knife's powers with it not even hurting him.
When held captive by the demon Del, Dean tries to free himself and reach the knife which he has in his possession. After Del is captured, Dean turns the knife over to Linda Tran who uses it to kill Del in revenge for his torture of her.
Going after the demons stealing people's souls, Sam arms himself with the knife. Sam kills the demon possessing Mr. Richie, but the knife is taken from him by the one possessing Sister Agnes. In response, Sam starts an exorcism, continuing it with a recording on his phone. Though Agnes manages to smash the phone before she can be exorcised, the exorcism allows Sam to retrieve the knife and stab her in the back with it, killing her.
- Azazel and Crowley are the only two high-level demons whose vulnerability to the knife has never been tested; but Azazel died before the knife was introduced and Crowley has always avoided being stabbed with it. The lengths that Lilith and Ruby went to when training Sam in the use of his powers made it seem like the knife wouldn't be able to kill her.
- Ruby's Knife as reproduced by angelicfoodcake