|“||Knights of Hell are hand-picked by Lucifer himself. They are of the first-fallen, first-born demons.||”|
— Henry Winchester
in As Time Goes By
A Knight of Hell is a unique breed of demon created by Cain, a knight himself, through the Mark that he bore. The Knights are thought to be among the oldest and most powerful of their kind, their exact rank in the hierarchy of Hell is not stated; however, they appear to be figures of awe among most demons, and refuse to obey demons they consider inferior to themselves.
In 1863, Cain retired from his position, inciting backlash from the Knights, who tried to tempt him back into his old ways by kidnapping his human wife Colette. In revenge, Cain slaughtered all of them save himself and his former lover and subordinate Abaddon, who managed to escape. Until she appeared in the year 1958 and again in 2013, it was believed that all the Knights had been exterminated by archangels. While Abaddon, too, was ultimately killed in 2014, her killer (Dean Winchester) was transformed into yet another Knight by the Mark of Cain, unofficially continuing the Knights' bloody legacy. However, this was brief as Dean's brother cured him, leaving Cain the only Knight until his own death, making the Knights of Hell extinct.
The Knights of Hell were created by Cain, and were thought to have been hand picked by Lucifer by the Men of Letters. Cain personally built the order of Knights and trained them himself which means the rank itself must have been at least 6,000 years old. Cain was their commander, leading them as they committed atrocities on Earth. They are represented by a sigil in a pre-enochian language, further indicating that the idea alone of the Knights of Hell had very ancient roots. The said sigil has been found in St. Bonaventure Convent in 1958.
After Cain fell in love with Colette in 1863 CE, the Knights sought to reclaim their leader by kidnapping Colette, whom Abaddon then possessed. Cain killed most of the Knights with the First Blade in his rage, but Abaddon escaped whilst tricking him into killing Colette. His promise to Colette not to kill anymore kept him from gaining revenge on Abaddon, and he retired. The Men of Letters believed that the extermination had been performed by archangels, though the demons of Hell knew the truth.
That the extermination had become a "legend" by 1958 indicates that Abaddon had either not been active on Earth or, as Cain apparently did, she kept her presence on Earth secret from even the Men of Letters long enough for the Men of Letters to conclude that all the Knights of Hell had died. In 1958, however, Abaddon resurfaced to kill Father Max Thompson and put a stop to his attempts at "curing" demons. She also worked with other demons to steal souls from innocent people and turn them into demons. This was discovered by Henry Winchester and Josie Sands who attempted to stop them and succeeded but were unable to stop Abaddon. To stop her from killing Henry, Josie offered herself to Abaddon instead. Knowing that she could learn more of the Men of Letters Abaddon accepted and possessed her. She later learned much of them and slaughtered the Men of Letters, and traveled into the year 2013.
Abaddon attempted to take over rulership of Hell by killing the King, Crowley, until Dean killed her. Cain remains retired, though he does consent to help Crowley and Dean Winchester kill Abaddon by giving Dean his mark and allowing him to use the First Blade on Abaddon, should they be able to find it. He also requests Dean kill him when he's done with Abaddon as like Abaddon, the Blade is the only thing that can kill him. In a final confrontation with Dean, Abaddon was killed by him with the First Blade after the Mark of Cain granted him immunity to her powers and telekinesis. Later, when Dean attempted to kill Metatron, he was killed by him instead, and the Mark of Cain transformed him into a Knight. Dean was later cured by Sam, leaving Cain the only Knight left once more.
After killing Abaddon's demons when they attacked his house, Cain fell back under the Mark of Cain's influence and started to slaughter his own bloodline as he saw them as "tainted." This led Dean, Sam, Crowley and the angel Castiel to team up to bring him down. After a brutal fight, Dean gained the upper hand and killed Cain, leaving the Knights of Hell extinct.
As a type of demon, Knights of Hell are evil spiritual entities that were created from human souls being stripped of their humanity. As a result of having been created through the Mark by Cain, Knights of Hell are "very pure" and "very strong" demons. They are called the first demons, making them among the oldest of their kind; this would mean that they were made shortly after the creation of Lilith herself (the very first demon).
The King of Hell outranks the Knights of Hell and they are expected to serve him, but they may stage a coup if they disapprove of the current King. The Knights of Hell are higher-ranked than common demons and most likely Crossroad Demons. They usually command great respect from their fellow demons and have their own subordinates: Abaddon had at least one demon who served her in the past, and she had assembled a group of demons willing to turn on Crowley and help her become Queen of Hell who feared and served her until her death. Larry Ganem called Abaddon a "hired gun," which would indicate that they may be willing to work for other parties for a price. Alternatively it could mean they are simply subservient to higher demons.
What a Knight of Hell looks like in its true form is unknown, but given descriptions of other demons' true faces, it is likely grotesque. On Earth, its true form manifests as a cloud of black smoke. A Knight of Hell may possess a human in order to interact with the physical world and its inhabitants. Most of the time, its host will not look any different than it how it did before she was possessed, but her eyes may change colors on occasion (such as when the Knight of Hell is extremely angry or wanting to intimidate its enemies) to reveal her possession. They have the completely black eyes typical of most demons. Certain other beings, such as other demons, can perceive a Knight of Hell's true form even when it is in a host, but ordinary humans are limited in the sense that they can only perceive its vessel or, if the Knight is not in a vessel, its smoke form. They were depicted as skeletal creatures wearing a horned helm in the notes of Tara.
Powers and abilities
A Knight of Hell is a particularly strong type of demon; in fact, Crowley indicated that a single Knight of Hell is more dangerous than a group of ordinary demons. Knights of Hell are more powerful than ordinary demons because while ordinary demons receive their power either from Lucifer (an archangel), or torture while in Hell, the Knights revived their power from The Darkness through the Mark given to Cain.  A Knight of Hell has powers that are rare and even unheard of among other demons, and demonstrates fewer weaknesses than most other demons do.
- Possession - Knights of Hell possess human bodies and take control of them, using them as their hosts on Earth. Notably, they can be inside two humans at once by inserting a portion of their essences into a second human while the majority of the Knights' essences remain in control of the first. However, each time this happened, it only took place for several moments before the Knight in question exited the second human and returned to her original host, leaving it unclear if Knights of Hell can possess two humans at once over a long period of time or if they can only perform split possessions temporarily.
- Biokinesis - A Knight of Hell is capable of making humans bleed profusely from their eyes, resulting in permanent blindness.
- Immunity - Unlike most demons, Knights of Hell are immune to exorcism rites, churches, and the worst effects of the demon-killing knife. They are also more resilient to holy fire than lesser demons, as they retain the ability to move their hosts' bodies when it is burning with holy fire, unlike other demons. Cain displayed partial immunity to a devil's trap: he was trapped by it though he stated it couldn't hold him long and still possessed his incredible strength and telekinesis.
- Super Strength - Knights of Hell have inhuman physical strength. Abaddon killed two men with her bare hands; one by slashing his throat open with one stroke of her fingernails, and the other by quickly and brutally thrusting a hand into his abdomen to fatally damage his vital organs, wounding him enough to kill him soon after. Dean was able to casually knock Crowley (the King of Hell) about to toy with him. Cain had an incredible level of strength, able to casually overpower other demons. He retained at least some of this strength in a devil's trap to the point that he was able to casually block Dean Winchester's blows.
- Telekinesis - Knights of Hell can move objects and people with their minds. They can use this power to throw human adults through only a hand gesture. Due to his level of sheer power, Cain retained telekinesis even in a devil's trap, throwing Dean around once and calling the First Blade to his hand.
- Invulnerability - Knights of Hell are little affected by damage dealt to their hosts, even injuries as severe as being stabbed, gunshot wounds, decapitation, and dismemberment. They may not be as tuned in to physical sensations as humans are, as Abaddon did not even notice that her hands were missing until Dean pointed it out to her. Contrarily, Cain felt such pain that losing a single hand defeated him. However, Cain was also in a devil's trap at the time which bound most of his powers and probably contributed to this.<ref>The Executioner's Song</ref> They can only be killed by the First Blade and at least Cain was unaffected by an angel's white light.
- Telepathy - By blowing a portion of her essence into a human, a Knight of Hell has the ability to access that human's memories to see and hear what that human had seen and heard. The Knight appears to be able to instantly identify and access specific memories she wants to see, rather than having to shift through all of a human's memories.
- Immortality - Knights of Hell will not die of age nor disease, and have the potential to live forever.
- Weather manipulation - A Knight of Hell is capable of causing weather phenomena. For example, an infuriated Abaddon caused thunder and lightning by screaming, and Cain's arrival caused gusts of wind.
- Super stamina - Knights of Hell do not require food, water, or sleep to maintain themselves.
- Terrakinesis - Knight of Hells can cause ground tremors. Abaddon used this power to split the ground of a church before she had even physically arrived there. Cain's mere arrival caused local tremors.
- Flight - When outside of their hosts, Knights of Hell can fly or hover above the ground.
- Tactile Exorcism - A Knight of Hell can expel another demon from her host and send her back to Hell simply by grabbing the demon's host by the neck.
- Teleportation - Knights of Hell can disappear from one location and reappear in another instantaneously.
- Apporting - A Knight of Hell can transport objects and people to different locations by touch.
- Skilled Fighters (Possibly) - Seeing as Cain trained them all, they were all probably very good at fighting.
Although the are some of the first-existing, oldest, and most powerful demons, a Knight of Hell is subject to some of the weaknesses that most demons have.
Harming, Misleading or Trapping
- Devil's trap - A Knight of Hell can be stripped of its powers if placed in a devil's trap. The trap has much the same effect if it is placed on or inside of the Knight's host instead, with the additional effect of severely restricting the Knight's ability to move. However, Cain is partially immune to a devil's trap's powers, being bound by one but still retaining his superhuman strength and telekinesis. He also states that a devil's trap can't hold him for long and seems more amused than annoyed to be trapped, indicating that at least for him, devil's traps aren't a big problem.
- Holy fire - While holy fire cannot kill Knights of Hell and they are more resistant to it than lesser demons are, they still find it to be extremely painful, to the point that Abaddon abandoned her host and fled when it became engulfed in holy fire.
- Holy water - Contact with holy water causes Knights of Hell to react as if burned. It was used to great effect on Abaddon, causing her to stagger backward and cover her face in pain for a short period of time without attacking her targets; Dean was similarly incapacitated despite additionally bearing the powerful Mark of Cain. Cain's vulnerability to holy water is yet untested.
- Angel Blade - It is likely that an angel blade can hurt a Knight of Hell, similar to the demon knife, given that Abaddon took care to disarm Dean of his when he confronted her with it. However these blades most likely cannot kill Knights, as the First Blade was needed to kill Abaddon.
- Demon-killing knife - Although the knife cannot kill a Knight of Hell, it is able to temporarily incapacitate one not bearing the mark: it caused Abaddon enough pain to bring her to her knees. However, Cain was completely immune to the knife. Dean's susceptibility to the knife was never tested, as while threatened with it, it was never used on him, though his complete lack of fear of it implies that, like Cain, it would be useless against him.
- Demon Curing Ritual - A Knight can be turned back into a human using this ritual.
- Purified blood - An essential part of the ritual to turn a demon human. It hurts a Knight more than other demons, but they retain demonic mannerisms longer than other demons as well despite it turning them more human.
Banishing and Killing
- Death's Scythe - This scythe can most likely kill a knight of hell, should they not bear the Mark of Cain. However, since knights of hell were created by Cain through the Mark (and therefore the Darkness), it is unknown what effect the scythe has on Knights.
- The First Blade - The First Blade, when powered by the Mark of Cain, is the only weapon that can kill a Knight. This was proven when Cain slaughtered the other Knights with it, when Dean killed Abaddon with it and later Cain.
- Angels/Archangels - In Devil May Care, Abaddon is shown to be weary when she sees an angel, so it is implied that Angels can harm the Knights. Higher Angels such as Seraphim and Archangels may be able to even kill them.
- The Darkness - As their and The First Blade's power source, The Darkness can kill any Knight of Hell.
- Death - As bringer of Death he can kill them. Death stated that whoever bears the Mark of Cain cannot be killed, even by him. However, he is able to remove the Mark, which would then allow him to kill Cain.
- God - As a primordial being, God has the power to kill a Knight of Hell. Like Death, if God removed the mark from Cain's arm, he could then kill him.
Known Knights of Hell
- Ironically, despite the power and status that the Knights commanded, at least two of them (Abaddon and Dean) were black-eyed, which usually denote low- to mid-tier demons. Cain on the other hand, never exhibited such eyes, even when he used his powers.
- Before it was confirmed by Cain that he had killed all other Knights (at the time) excluding himself and Abaddon, it was speculated by fans that other high-class demons, e.g. Alastair (due to his high resistance to the demon-killing knife), had also been Knights.
- The number of Knights that existed before Cain's slaughter is unknown. As Cain referred to having slain "the Knight's of Hell," there were at least two yet-to-be-named Knights who participated in Colette's kidnapping alongside Abaddon and were killed by Cain in retribution in 1863. Its indicated there were several however, as Cain called it a "demonic order."
- When a Knight of Hell is killed by the First Blade, they emit a massive red light that resembles the visual effects of Cain's smiting ability, rather than the brief flashes light seen with most other demon deaths. When Cain was killed, the effect wasn't shown though there was a clap of thunder in the background.
- As shown anyone killed possessing the Mark of Cain will return as a demon, who as a result of the Mark are immune to anything including Ruby's knife. It is also implied by Cain that the user of the Mark cannot use the blade on themselves. This would mean a demon with the Mark is completely immortal, however Cain indicated that one bearer of the Mark can kill another permanently using the First Blade. This is proven in fact when Dean killed Cain.
- Although Knights can be cured by the Demon Curing Ritual, they, or at least ones with the Mark of Cain, still retain demonic mannerisms longer than other demons do, including the King of Hell Crowley. This indicates they have a stronger resistance to the ritual but not complete immunity as it does work.
- While the Men of Letters were aware of the Knights existence, despite their great wealth of knowledge, they seemed to know very little about the Knights themselves. For example, Henry Winchester was aware of their existence but, along with presumably all the other Men of Letters, believed them all to be dead before the reappearance of Abaddon who he was unaware was a Knight when she appeared either. The Men of Letters also believed that the archangels wiped out the Knights, something that most demons believed as well when in fact it was Cain. The Men of Letters also seemed to lack knowledge on how to defeat or kill a Knight: when Abaddon arrived, they knew who she was but tried an exorcism which they were unaware she was immune to. When Sam Winchester asked Larry Ganem how to stop her, he responded saying that they couldn't. Also, when Kevin Tran looked through the bunker's archives, he too couldn't find anything and resorted to asking Crowley.
- Season 9
- ↑ 1.0 1.1 1.2 1.3 1.4 Sacrifice
- ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 As Time Goes By
- ↑ 3.0 3.1 3.2 King of the Damned
- ↑ 4.0 4.1 Mother's Little Helper
- ↑ 5.0 5.1 5.2 5.3 5.4 5.5 5.6 5.7 First Born
- ↑ Abandon All Hope...
- ↑ 7.0 7.1 Reichenbach
- ↑ 8.0 8.1 8.2 Clip Show
- ↑ 9.0 9.1 9.2 9.3 Devil May Care