Arthur Ketch

"We don't need a conscience. Such a trite idea, but we firmly believe the ends do justify the means."

- Arthur Ketch to Mary Winchester

Arthur Ketch (b. February 21, 1974) is a former member of the British Men of Letters. He was killed by Mary Winchester but was resurrected by Rowena MacLeod's Resurrection Seal. Following this, he begins work as a mercenary hunter and joins Asmodeus' search for Jack, only to later become a mole in his organization for the Winchesters. In an effort to gain redemption for his past, Arthur rescued the archangel Gabriel and went on to join Dean Winchester in an effort to rescue Mary and Jack from Apocalypse World.

Background
Like all members of the British Men of Letters, Arthur attended the Kendricks Academy. He attended it alongside Mick Davies and Lady Toni Bevell with whom he had a relationship. After graduation, Arthur became one of the organization's top operatives, utilized for torture and assassination.

According to Arthur, he has been in multiple war zones though in an unknown capacity.

Season 12
Arthur Ketch is first mentioned while Lady Toni Bevell is torturing Sam for information. When all their methods prove fruitless, Ms. Watt suggests bringing in Ketch; however, Toni is very much against it.

He is also shown in a flashback killing a vampire, identifiable by the tattoo on his hand.

Later on, Mick Davies retrieves Toni and informs her that he has sent for Mr. Ketch, who is shown preparing to leave the UK. This leaves Toni visibly uncomfortable.

In American Nightmare, Mr. Ketch drives up to the Impala on a motorcycle (first seen in the previous episode) and stares at it for a moment before driving away. He later tracks down and kills Magda Peterson, telling someone on the phone that he cleaned up the Winchesters mess and they were correct about the Winchesters being unable to kill Magda.

In LOTUS, Arthur rescues the Winchesters and Castiel from the Secret Service and orders Castiel to wipe their memory before introducing himself. That night, Arthur explains that his job is to "strongly encourage" the Winchesters to work with the British Men of Letters and he was sent by Mick Davies after Sam called him and hung up. Arthur has Castiel confirm that he's not lying and shows them his arsenal of weapons, including a hyperbolic pulse generator capable of exorcising a demon from its vessel. Recognizing its potential, Sam asks to borrow it and for Arthur to trust them. Arthur eventually gives the Winchesters the generator, enabling them to force Lucifer from Jefferson Rooney and send him back to Lucifer's Cage.

Six weeks later, Castiel contacts Arthur and Mick to help him and Mary find Sam and Dean who have been taken prisoner by the Secret Service. The two men are impressed to learn that the brothers had in fact borrowed Arthur's gadget in order to deal with Lucifer himself. They agree to help in hopes that it will earn them the trust of the American hunters, and through their connections, Arthur and Mick locate Sam and Dean near Site 94.

Once the four encounter Sam and Dean, Arthur is unimpressed to learn that they left survivors. Sam insists the people pursuing them were just soldiers doing their job, though Arthur considers it "unprofessional". Sam, Dean, and Castiel head to Mary's car while glaring at Arthur suspiciously. Arthur and Mick watch them drive off and share a knowing look at each other. It is later revealed that Arthur went back and killed all those involved in Sam and Dean's imprisonment, including Agent Rick, Agent Camp, the soldiers and the coroner. Mick reports this while noting that cleaning up loose ends is Arthur's job.

In Stuck in the Middle (With You), Mary visits Arthur after stealing the Colt and tells him the story of its theft from Ramiel. Mary is enraged that Arthur sent her after a Prince of Hell which got Wally killed and threatens to destroy the British Men of Letters if something happens to her sons. Arthur apologizes, claiming not to have known that she was going after a Prince of Hell. Arthur and Mary discuss the legend of the Colt as an excited Arthur unwraps it.

In Family Feud, Arthur accompanies Mary Winchester on a rugaru hunt. Arthur tells Mary he is thoroughly impressed with Mary's hunting skills after she kills three rugarus by herself. Arthur later takes Mary to her hotel and tells her she is one of the best hunters he has ever seen. Arthur also says she is an excellent liar. Arthur tells Mary she should forget her sons as they are a weakness to her.

In The Raid, Mary and Arthur take out a vampire nest together and Arthur expresses his dislike for them trying to recruit the Winchester brothers when they have Mary. Arthur later visits Dean at the Men of Letters bunker and sits down for a drink with him. Rather than trying the sales pitch like the other British Men of Letters, Arthur is frank with Dean about his motives, telling Dean that he is a killer and the British Men of Letters offer him the best chance to express his talents. Arthur sees Dean as the same as him and the two decide to take down a vampire nest together. At the nest, Arthur initially arms himself with a gun but decides to use a machete instead like Dean. The two men find only one vampire hiding in the nest and Arthur beats upon her before Dean stops him to try things his way. When Dean promises to grant the vampire a quick end, she tells them that her nest is going after the British Men of Letters.

Alarmed, Dean and Arthur rush back to the British Men of Letters compound to find that Sam has killed the Alpha Vampire and the surviving vampires have fled. Mick berates Arthur who tells him he was trying to recruit Dean and would've succeeded if Mick's operation hadn't screwed things up. He then punishes the rogue hunter Pierce Moncrieff who they were previously working with.

In The British Invasion, Arthur sleeps with Mary following a successful hunt. Mary seems tempted to bond with him further but Arthur seemingly disapproves though he appears intrigued by Mary's attempt to have "the best of both worlds." Arthur is later called back to the British Men of Letters headquarters by Doctor Hess. The two wait for Mick to arrive. Mick shows disobedience and Arthur is ordered to kill his former friend. While the two stare down at Mick's body, Arthur appearing to have some remorse or regret for his actions, Hess announces that every single one of the American hunters must be eliminated.

In The Memory Remains, Arthur sends a text to Sam pretending to be Mick, checking in if the brothers are home. Sam replies they are not, allowing Arthur to enter the Bunker with a few subordinates so they can wiretap it and search for The Colt. While scanning Dean's room, Mick comes across a photo of Mary with a 4-years-old Dean. Once the operation is complete, Arthur returns to his own headquarters, taking the photo with him. By the time Sam and Dean return home, Arthur calls to inform them that Mick has been sent back to London so they must report directly to him, even if they don't like it. After the call, Arthur listens to the brothers' conversation through the wiretap he set up and hears Dean insult his motorbike. Arthur stares at the photo he stole while listening.

In Twigs & Twine & Tasha Banes, Mary discovers Mick's body as well as the fact that the Brits are now targeting American hunters. She angrily confronts Arthur about this. Arthur initially tries to brush Mick's death off as "an unfortunate werewolf mishap", but Mary doesn't believe it, knowing werewolves don't shoot people. The two get into an argument, with Arthur claiming that his murdering of the US Secret Service agents and Magda Peterson as cleaning up after Mary's sloppy sons. Mary disagrees, and the two get into a fight. When Mary tries to make a run for it, Arthur knocks her out using a taser. He then ties her up to a chair and arranges for Toni Bevell to interrogate the hunter since Mary is still too precious of an asset to kill.

In There's Something About Mary, Arthur kills seven hunters, including Eileen Leahy, with his new pet hellhound.

Arthur visits Mary while she is being brainwashed by Toni into being a killer for the British Men of Letters. Mary tries to kill herself with Arthur's gun and begs Arthur to kill her as losing her will is the worst thing Mary can imagine. Apparently sympathetic and unwilling to kill Mary, Arthur assures her that it will all be over soon. He also introduces his hellhound to Toni who is disturbed.

Later, Arthur and three of his men ambush the Winchesters in the bunker, ending with Arthur's men killed and Arthur held at gunpoint by Dean. However, a fully-brainwashed Mary enters and forces her sons to release Arthur. Taking Dean's gun, Arthur forces the Winchesters and Toni, who he sees as expendable, to remain in the bunker as he and Mary leave. Arthur reveals that he is initiating a lockdown that will trap the three in the bunker with no power and water and the air being sucked out, resulting in their deaths within two to three days. He later tells an emotionless Mary that it will get easier killing people she doesn't remember loving.

In Who We Are, Arthur sends Mary names of hunters to kill and prepares for a massive operation to wipe out all of the American hunters and their families. After being unable to reach Mary, Arthur has Paige discreetly track her and discovers that Mary is in Lebanon, Kansas. Realizing what this means, Arthur leaves before hunters led by Sam storm the British Men of Letters compound and kill everyone inside. Moments after reaching Mary's mind, Dean awakens to find Arthur in the bunker, having murdered Toni. Dean and Arthur engage in a brutal hand-to-hand fight through the bunker's main room that ends with Arthur holding Dean at gunpoint. Before Arthur can kill Dean, he's shot in the arm by Mary whose mind has returned thanks to Dean and Toni. Arthur tells the Winchesters he knew both of them were killers before Mary executes Arthur with a shot to the head. His body is later covered with a sheet by Mary and Dean. It's later revealed that the Winchesters dumped Arthur's body into the waste canal.

Season 13
In War of the Worlds, the Winchesters investigate a series of witch murders and are shocked to discover what appears to be a bearded Arthur Ketch following one of the victims. The Winchesters meet Daniela, Arthur's latest victims who reveals she managed to escape him and they use her as bait to successfully capture the man who claims to be Arthur's twin brother Alexander, though Dean remains dubious of his story. "Alexander" tells the Winchesters that Arthur wasn't naturally amoral, was "loyal to a fault" and most likely regretted some of the things he did to them. "Alexander", who was hunting Rowena MacLeod, claims to be working as a mercenary hunter and is hunting for Rowena simply because she is a witch. After getting a weird call from Castiel, the Winchesters leave "Alexander" behind in the bunker.

During a fight with a group of demons, "Alexander" suddenly appears to help, saving the Winchesters' lives and killing one with an angel blade. When asked, he explains that he had a hidden lock pick that the Winchesters would've found if they'd done a thorough cavity search. The fight causes Dean to realize that Arthur and Alexander are truly one and the same as he'd suspected as Dean recognized Arthur's fighting style along with other inconsistences. Arthur finally admits that Dean is right though he had mostly told them the truth about himself. Arthur is now separated from the British Men of Letters under his new alias of Alexander with his former employers wanting him dead for it if they knew. He is also working as a mercenary hunter. Arthur explains that long ago, he made a deal with Rowena where she supplied him with a Resurrection Seal in exchange for his help in escaping the British Men of Letters custody. After they had dumped his body, Arthur was resurrected. Arthur suggests to Dean that they are truly on the same side now which is why Arthur came to the Winchesters rescue instead of escaping. Not willing to trust Arthur, Dean attempts to kill him, wounding Arthur in the shoulder before he drops a smoke bomb and escapes on his motorcycle.

Later, now clean-shaven, wearing a sling on his right arm and dressed in his old suit, Arthur agrees to work for the Prince of Hell Asmodeus to help find the Nephilim Jack in preparation for Michael's upcoming invasion.

In Devil's Bargain, Arthur criticizes Asmodeus over leaving on an "important errand," allowing the escape of Lucifer and Castiel. Despite Arthur's open defiance, Asmodeus does not get angry and instead sends Arthur to kill Lucifer before he regains full power. Arthur eventually tracks Lucifer to Sister Jo's hall, but finds it empty and is confronted by the Winchesters and Castiel. Though Arthur attempts to convince the Winchesters to work with him, they have Castiel render Arthur unconscious instead and throw him in the Impala's trunk. Dean's plan, backed up by Sam and Castiel is to take Arthur back to the bunker, shoot him again, burn his body and scatter his ashes.

As the Winchesters and Castiel face off with Lucifer and Sister Jo, Arthur suddenly enters and flings a demon bomb at the two angels. Lucifer is able to teleport them out before Arthur's attack can succeed however. Though the Winchesters are annoyed by Arthur apparently helping Lucifer to escape, Arthur points out that he opted out of his own escape and risked himself to save their lives again. When questioned how he escaped, Arthur simply states that "I'm Ketch" and he'd found the demon bomb in their trunk and thought that it would work on Lucifer in his weakened state.

Stating that he knows they might not listen, Arthur again suggests that they work together to go after Lucifer. As the Winchesters continue to remain skeptical, Arthur comes clean that he is working for Asmodeus. Arthur suggests that he can act as a mole for the Winchesters against Asmodeus for the sake of everyone. Though Arthur acknowledges that he knows the Winchesters think he's a monster, even he has to draw the line somewhere "and letting Lucifer free upon the Earth, well as it turns out that's my line. Not to mention the whole Michael situation." While he knows that the Winchesters want to kill him and can't forgive him, Arthur asks that they do so after he proves useful as the lesser of "at least three evils." Ultimately, the Winchesters and Castiel agree with Arthur's request. Later, the Winchesters acknowledge that while they can't trust Arthur "even a little," they do need him "for now" and plan to kill Arthur when he is no longer needed.

After returning to Asmodeus, Arthur reports that he missed Lucifer by seconds and he will find him again. When Asmodeus expresses worry about killing Lucifer before the Winchesters can use him to open up a gate to "Michael Land," Arthur points out that Lucifer is getting stronger again and even as good as Arthur is, he can't beat Lucifer at full power. Asmodeus presents Arthur with the archangel blade, the only known weapon capable of killing an archangel. A confused Arthur questions how they will use the blade since the lore states that it is only effective in the hands of an archangel, causing Asmodeus to introduce Arthur to the captive Gabriel.

In The Thing, Arthur is summoned before Asmodeus, but is forced to wait by another demon. Annoyed with waiting, Arthur eventually slips past the demon guard and witnesses Asmodeus injecting himself with Gabriel's grace. Asmodeus, angered by Arthur's impudence, dismisses him to wait again.

Later, Arthur is called before Asmodeus again and is informed that the Winchesters are trying to open a rift into the Apocalypse World using a ritual from the Demon Tablet that requires, amongst other things, "a whole mess" of archangel grace. Arthur acknowledges that he's learned that Castiel has been seen in Syria and admits to not telling Asmodeus as Asmodeus didn't ask and he was trying to gather more information. Angered with Arthur's continued audacity, Asmodeus beats him to a pulp and states that Arthur is worse than most demons "and I know them all." Asmodeus recognizes that the battered Arthur desires redemption for his previous actions, but states that Arthur can't be redeemed and so he belongs to Asmodeus.

After Asmodeus leaves, the battered Arthur removes a loose tooth and decides to escape with Gabriel. Grabbing the terrified Gabriel and the archangel blade, Arthur drags Gabriel from Crowley's old lair, killing the demon guard he had previously clashed with using the archangel blade.

After the Winchesters return to the Men of Letters bunker with the Seal of Solomon, they discover Arthur waiting for them. To their shock, Arthur reveals the battered Gabriel. Arthur explains that Asmodeus had been holding Gabriel prisoner until Arthur rescued him. After Arthur tells them that he heard they need an archangel for a spell, Sam admits that they need Gabriel's grace, to Gabriel's obvious terror. Calming Gabriel down, Arthur presents Asmodeus' next dose of Gabriel's grace, stolen along with the archangel blade. In return, Arthur asks for sanctuary at the bunker since Asmodeus will chase him to the ends of the Earth for his actions. To both Sam and Arthur's obvious shock, Dean agrees to Arthur's proposal since it can potentially help them get their mother and Jack back.

As the Winchesters prepare to open the rift to Apocalypse World, Arthur arrives and announces that he'll join Dean as he wants to be a world away from Asmodeus. To Sam's surprise, Dean agrees to allow Arthur to join him when he won't allow Sam. Dean tells Sam that he doesn't care if Arthur survives or not unlike Sam and in fact hopes he doesn't, something that Arthur takes in stride. Once the rift opens, Dean and Arthur pass through into Apocalypse World together, leaving Sam and Gabriel behind.

In Bring 'em Back Alive, Arthur and Dean wander the area with Arthur practicing stealth in unfamiliar territory while Dean is put off by his methods. The two soon witness a squad of angels lining up humans and executing them on the bridge in Michael's name. Arthur stops an a furious Dean from getting involved before he notices Dean's shocked expression at a female human soldier who is captured for questioning.

Arthur and Dean then continue on as Arthur questions Dean about Charlie before Dean is grazed by a bullet. When Dean attacked by a crazed man who restrains him, Arthur comes to his aid and tackles the man for answers about where he was going to take Dean. However, the manages to pin Arthur and hold a knife to his neck but Dean took advantage of the distraction and freed himself and shoots bullets in the air to stop him, saving Arthur. Dean repeats Arthur's question and after shooting the man in the leg, he learns there is a camp for human prisoners.

Arthur and Dean head in the direction of the camp and Arthur is given angel-killing bullets which amazes him as they travel. When Dean feels weakened, Arthur examines him and sees the bullet Dean was grazed by was laced with poison. Fortunately, Arthur was familiar with it and he proceeds to treat the wound and Dean gives him his answer about Charlie and how he failed her. On the way, Dean gives him his answer about Charlie and how he failed her. Arthur returns it by stating he let many comrades die on the battlefield because of orders and decided to help Dean save Charlie.

Eventually, they make it to the camp where they see Charlie taken out to the middle of the camp where she was to be executed by decapitation. However, Dean threw a grenade which allows him and Arthur to storm the camp kill the guards before proceeding free Charlie from her binds. Dean managed to procure Charlie and they escape the area.

After getting a safe distance away from the camp, the three head into the forest where the rift is located. Arthur watched as Dean informed Charlie of everything and they learn Jack and Mary have formed a resistance against Michael and the angels. Charlie revealed she last heard they were setting up an outpost in Dayton, Ohio.

The three make it to the rift but as they are out of time before the rift closes, Arthur implores Dean to return to the Main Universe while he remains behind in Apocalypse World to learn Michael's plans, find Mary and Jack and help the resistance coordinate for Dean's inevitable return with reinforcements. At that moment, angels appear and Arthur and Charlie hold them off as they tell Dean to head back.

In Exodus, Arthur joins Charlie on a mission to ambush an angel death squad. However, it proves to be a trap and the angels take Charlie captive and force Arthur to surrender his weapon. The angels torture Arthur and Charlie for information, but Arthur refuses to break and taunts the angels. The angels then bring in an expert torturer: the alternate Castiel. Arthur watches in horror as Charlie is tortured by Castiel before Dean, Sam, Mary, Jack and Castiel arrive to rescue them. Released from his shackles and supported by Dean, a battered Arthur comments on Dean rescuing him for once and jokes that "its about bloody time."

Arthur joins the exodus back through the rift to the bunker, leading the way with Castiel. Upon seeing Rowena on the other side, Arthur and Rowena exchange surprised looks before Arthur moves on, apparently not pleased to see Rowena. During the celebration that follows, Arthur shares a drink with Charlie.

In Let the Good Times Roll, Arthur is mentioned to be "out doing Ketch things" by Bobby while discussing their current situation with Mary.

Skills and Abilities
He is a professional killer. He has murdered any "leftovers" from the Winchester's work without any difficulty. He is quite confident about his abilities, as when he and Dean went after a vampire nest, he choose to use a machete, instead of the Vampire Irradiation Gun because he considered it far less challenging.
 * Forensics Specialist - Arthur was able to clean up all evidence of any sort of supernatural event.
 * Interrogation - He is also a very capable torturer and was often used by the British Men of Letters for this purpose.
 * Expert Combatant - Arthur is also a highly adept fighter, as he was able to overpower Dean for a while, though Dean was injured and disorientated at the time. He apparently has a unique enough fighting style that Dean was able to see through his disguise as "Alexander" just from seeing him fight some demons based on Dean's own fight with Arthur.
 * Marksmanship - Arthur is a skilled marksman. During the Liberation of the Silo, Arthur was able to gun down several angels with little difficulty.
 * Poison Knowledge - Due to his time amongst the British Men of Letters, Arthur possesses knowledge on certain poisons and their antidotes. He was able to create an antidote for a poison similar to one used by the British Men of Letters to save Dean's life.
 * Self-Resurrection - Arthur was able to come back from the dead completely healed, thanks to Rowena implanting a Resurrection Seal within him. However, this has to be recharged for Arthur to use it once again.
 * High Pain Tolerance - Arthur shows a remarkable pain tolerance, as he stayed conscious after he was beaten by Asmodeus. He also refused to break under torture and even taunted the angels torturing him. Even while in a weakened and battered state to the point that he couldn't stand on his own, Arthur was still conscious enough to crack a joke about his rescue.

British Men of Letters Operative
As a member of the British Men of Letters, he has access to its vast weaponry. The engineers of the British Men of Letters have spent years blending sorcery and technology to produce an advanced arsenal to combat supernatural threats. Arthur appears to have lost all of the devices he gained while working with the British Men of Letters following his separation from the organization.
 * Grenade Launcher: Part of Arthur's arsenal, it was used to blow up a Secret Service vehicle.
 * Vampire Radiation gun.pngVampire Irradiation Gun: The British Men of Letters don't always have to cut off the heads of vampires to eliminate them as they have developed a tool that uses radiation to reorder the DNA of a vampire which turns the vampire's own blood into poison that is lethal to them. It is said to be very effective on large vampire nests.
 * Hyperbolic pulse generator: A device capable to targeting specific angels or demons and exorcising them safely without harming the host. It is capable of removing even an archangel.
 * Anti-Vampire Device: Device that sprays a gas deadly to vampires and used by Arthur and Mary Winchester during Project V. Destroyed by Pierce Moncrieff.
 * Arthur's car: Though he preferred driving his motorcycle, Arthur was seen driving a car a few times. The trunk of this car contained his arsenal from the British Men of Letters.

Mercenary Hunter
As a mercenary hunter, Arthur's equipment is greatly reduced and tends to be more along the lines of a regular hunter rather than a British Men of Letters operative.
 * Lock Pick - Hidden somewhere that could only be found with a full cavity search in case he needs to escape.
 * Angel Blade - After escaping from his chains in the Men of Letters bunker, Arthur stole an angel blade to come to the Winchesters' rescue. After Arthur's true identity was exposed, it was taken back by Sam Winchester. Arthur later had one given to him by Asmodeus to hunt Lucifer but had it taken from him by the Winchesters and Castiel when he was captured by them.
 * Demon bomb - After escaping the Impala's trunk, Arthur took a demon bomb from the arsenal and used it in a failed attempt to kill Lucifer.
 * Archangel Blade - After deciding to escape with the archangel Gabriel, Arthur stole the archangel blade that Asmodeus had managed to acquire. During the escape, Arthur used the blade to kill a demon and later turned it over to the Winchesters.
 * Gabriel's grace - While escaping Asmodeus' custody, Arthur stole some of Gabriel's grace from him. Arthur later turned it over to the Winchesters in order to open a rift into Apocalypse World.
 * Angel-killing bullets - After Dean and Arthur encounter a bounty hunter, the two men are able to retrieve weapons loaded with angel-killing bullets from amongst his things. Arthur uses the bullets to kill several angels during the Liberation of the Silo and then to battle four angels alongside Charlie Bradbury. He continues to utilize the bullets during conflicts with the angels of Apocalypse World during his time as a resistance member there.
 * Arthur Ketch's motorcycle - Arthur owns a black Norton Commando motorcycle which he uses as transportation. After being killed by Mary it ends up in the possession of the Winchesters. Arthur reclaims it after his resurrection.

Personality
Arthur presents himself as a gentleman of sorts with a strong British accent. He has no qualms about killing people and considers it his job to clean up loose ends. He believes stalking the Winchesters and killing all those they choose to spare as being "professional". He can be a bit of a show off as seen during his formal introduction to Sam and Dean, when he blew up a vehicle belonging to the Secret Service and proudly presented the Winchesters with his vast weaponry. His well-dressed appearance and charming manners clearly hide a much more sinister personality, which Sam, Dean and Castiel begin to notice over time. In a frank conversation with Dean, Arthur calls himself a killer and admits that when he doesn't kill, it bothers him and he works for the British Men of Letters due to their ability to supply him with targets. Arthur sees himself as similar to Dean in this regard and seems to regard Dean as something of a kindred spirit.

Despite his ruthless personality, Arthur does appear to care somewhat about others. After sleeping with Mary Winchester, Arthur brushed off the idea of them having a relationship, but did so in a way that indicated he had in fact wanted one with her. He also appeared somewhat intrigued by the idea of her having "the best of both worlds" by having both her family and hunting. Despite his cold-heartedness, Arthur does appear to have some genuine feelings and care for Mary. Starting as admiration, Arthur shows obvious upset that their relationship isn't more after they have a one-night stand. While ordered to kill the American hunters, Arthur did his best to protect Mary in his own twisted way though he didn't hesitate to taser her from behind. He appeared to be genuinely distressed by her predicament of being brainwashed and went as far as to attempt to comfort her. Arthur also didn't seem to be able to bring himself to kill her, even at Mary's request despite his ruthless and cold-heartedness. He appeared disquieted by her heartlessness after she is successfully brainwashed. As "Alexander", Arthur makes it a point to ask after Mary and the look in his eyes when Dean responds is a major part of what convinces Dean that "Alexander" is in fact Arthur.

However, Arthur remains a cold-hearted, psychotic individual who believes the ends justify the means. He becomes disappointed in Mary when he realizes she is not as cold-hearted as he had hoped. He considers having a conscience as a trite idea, and considers Sam and Dean as "sloppy hunters" for sparing the Secret Service agents and Magda Peterson. He believes psychics and non-human entities are monsters that deserve torture and death and nothing more. Following his resurrection, Arthur apparently lost these beliefs or was willing to put them aside as he willingly worked for the Prince of Hell Asmodeus as a freelancer.

Arthur possesses a great deal of arrogance due to his skills. When Dean tells Arthur he is going to kill him, Arthur tells Dean that Dean won't but Arthur will greatly enjoy Dean trying. He also took great pleasure in taunting Dean through their fight. When asked how he escaped from the Impala's trunk, Arthur's response was simply "I'm Ketch." However, Arthur is aware that even his considerable skills have limits, telling Asmdoeus that even he can't defeat Lucifer at full power.

While posing as Alexander Ketch, Arthur stated that he wasn't naturally amoral, indicating it was something that he had become. Arthur also stated that he is "loyal to a fault" and that the Arthur that they had met was "an incredibly good company man. Not an easy job." While disguised as Alexander, Arthur further indicated that he regretted some of the things he did to the Winchesters. Indeed, after his deception was exposed, he claimed to have simply been a solider on the opposite side of a war rather than someone who had a personal stake in what was being done to the Winchesters. He also claimed to have mostly told them the truth about himself when in their captivity with the indication being that he was only lying about his identity and his return.

Following his resurrection, Arthur adapted a more mercenary mindset, continuing his work but only for those who paid him for it generally. This was seen as he made a deal with Asmodeus to find Jack for impending invasion of Michael.

When dealing with Asmodeus, Arthur acts fearless and snarky, criticizing Asmodeus' decisions openly and not backing down when Asmodeus attempts to intimidate him. In return, Asmodeus appears to respect Arthur and treat him more as an equal than a subordinate.

Following his resurrection, despite their checkered past, Arthur does appear to care about the Winchesters as at least allies if nothing else. As Arthur points out, he saves their lives twice while putting his own at risk and makes overt overtures towards reconciliation or at least not being enemies anymore. At the same time, Arthur recognizes that they can't forgive him and don't trust him, something he openly acknowledges and accepts. While the Winchesters refuse to trust Arthur, he is able to make a good enough argument to form an alliance, even revealing his alliance with Asmodeus as a show of his telling the truth.

According to Arthur, while he knows that the Winchesters consider him a monster, even he has to draw a line somewhere. For Arthur, his line is Lucifer running free upon the Earth and the threat of Michael's impending invasion.

According to Asmodeus, while Arthur acts like a cold-blooded killer, in truth, at least after his resurrection, Arthur really feels fear, regret and pain and wishes for redemption for his previous actions. On a few occasions, even while working for the British Men of Letters, Arthur showed signs of regret and remorse for his actions despite carrying on with them. While Arthur murdered Mick Davies on Doctor Hess' order, the expression on his face afterwards suggested that he had some remorse or regret for having done so. When talking to Mary Winchester, he told her that she doesn't know him and she doesn't want to in a way that suggested he possibly possessed some regret and maybe self-hatred for the things he'd done. This was further implied by his words to the Winchesters as "Alexander" in which Arthur implied he felt remorse over at least some of the things he had done to them as well.

Since his first death, Arthur has gained a sense of self-preservation and chose to flee the scene when Dean threatened him after he was exposed as Arthur instead of Alexander. He also chose to head to the Men of Letters bunker and Apocalypse World to get away from Asmodeus as he knew the consequences of his actions of freeing Gabriel.

On a personal level, Arthur at first has very little regard for the Winchesters. He is shown to believe that they have the only Winchester they need in Mary Winchester and only reluctantly agrees to trying to recruit them, mainly because he has no other choice. However, he at the least sees Dean as something of a kindred spirit due to both of them being, at times in Dean's case, ruthless killers. After his resurrection and separation from the British Men of Letters, Arthur appears to hold the Winchesters in a greater regard and treats them with more respect, possibly as he no longer has his judgment clouded by working with the British Men of Letters and because he has seen firsthand what they are capable of. While posing as "Alexander," Arthur implied that he regretted many of the things he'd done to the Winchesters and took their negative opinion of him during their interactions with each other following his resurrection in stride. During their time in Apocalypse World, Arthur developed something of an understanding and camaraderie with Dean, showing concern for his safety and backing Dean up in rescuing his friend. Arthur went so far as to reminisce about his own mistakes and how they were both similar and dissimilar to Dean's. When Dean rescues him from torture, Arthur goes so far as to crack a joke about it being "about bloody time" that Dean rescues him instead of the other way around.

According to the Prince of Hell Asmodeus in The Thing, Arthur is "more wicked than any demon I know. And I know 'em all." In return, Arthur admits that "I know who I am," but feels that he at least still has a soul unlike demons.

While dealing with the broken and battered Gabriel, Arthur displays a level of compassion for the archangel, calling him "a poor man" for what Gabriel suffered through at Asmodeus' hands. Notably, Arthur took the time to calm Gabriel down when he panicked over the Winchesters needing his grace. Though Arthur was impatient and rough with Gabriel while escaping Crowley's old lair, this appeared to stem from Gabriel's reluctance to cooperate and the urgency of the situation rather than Arthur simply being rough with him for refusing to help or simply not being human.

While talking with Dean in the Apocalypse World, Arthur shows some similar personality traits to Dean. Notably, when discussing Dean's guilt over the loss of Charlie Bradbury, Arthur tells him that the difference between them is that while Dean couldn't save his friends, Arthur never tried. Arthur is clearly burdened by this fact, calling it "duty and all that. Rubbish" with a tone of great regret. After he learns of Dean's history with Charlie and his guilt over her murder, Arthur agrees to help in the hopes that in doing so, he will be able to wash some of the stain off of his own hands.

When confronted with Charlie held hostage, Arthur surrendered rather than risk Charlie's life as he would have in the past. While watching Charlie's torture by Castiel, Arthur is visibly horrified to witness it despite his past as a torturer for the British Men of Letters and his previously stated beliefs about torture. Arthur appears to have developed a close friendship with Charlie during their time fighting together, working with her as a team, caring about her state during her torture and sharing a drink once they return to the bunker.

Physical Appearance
Arthur is a dark-haired Caucasian man who generally wears clean suits. He has a tiny Christian Cross tattoo on the back of his right hand. After his resurrection, Arthur ditched his suits and wore more casual clothes. He also grew a beard. Following the exposure of his resurrection, Arthur shaved off his beard and resumed wearing one of his old suits. For his disguise as Alexander Ketch, Arthur had his defining cross tattoo removed. When traveling to Apocalypse World, Arthur removed his suit and put on more casual clothes better suited for the mission, the same type he put on when visiting Dean at the Men of Letters bunker and attacking the Morest nest with him.

Killed By
As Arthur prepared to kill Dean, he was shot in the arm by Mary, defeating him. After Arthur told the Winchesters he knew they were killers, Mary executed Arthur with a shot to the head. He was later resurrected by his own Resurrection Seal.
 * Mary Winchester

Appearances

 * Season 12
 * Keep Calm and Carry On
 * Mamma Mia
 * American Nightmare
 * LOTUS
 * First Blood
 * Stuck in the Middle (With You)
 * Family Feud
 * The Raid
 * The British Invasion
 * The Memory Remains
 * Twigs & Twine & Tasha Banes
 * There's Something About Mary
 * Who We Are
 * Season 13
 * War of the Worlds
 * Devil's Bargain
 * The Thing
 * Bring 'em Back Alive
 * Unfinished Business
 * Exodus
 * Let the Good Times Roll

Trivia

 * Arthur appears as the killer of a vampire in Keep Calm and Carry On when Lady Toni Bevell describes the British Men of Letters activities. He can be identified through both the cross on his hand and the fact that close observation of the blurry killer shows that its clearly Arthur Ketch.
 * He is the British Men of Letters member with the most appearances.
 * While Ms. Watt implies he's a very proficient torturer, Toni describes him as a psychopath. In return, Arthur calls her "a neurotic, overreaching time bomb" and admits to being her ex-boyfriend and the one person who saw her actions coming. As Arthur is Toni's ex-boyfriend, their dim opinion of each other may come from their former relationship. Indeed, while Arthur is shown to be a remorseless killer in general, after killing Mick Davies he appeared to show regret for his actions, indicating he is not totally unfeeling and uncaring. After torturing a shapeshifter, Mary notes that Arthur did indeed enjoy it. While posing as Alexander Ketch, Arthur himself indicated that he does indeed possess regrets for at least some of his actions regarding the Winchesters. Asmodeus stated that Arthur does in fact feel regret and wish for redemption.
 * His name is possibly a reference to the famous executioner Jack Ketch, who made a name for himself as the somewhat barbaric executioner of political offenders in the late 1600s.
 * Arthur describes himself as an artist who paints in many colors.
 * According to a shapeshifter, Arthur's eye twitches when he lies. Arthur's response is that his eye twitches all the time, indicating that he is constantly lying.
 * Arthur indicates that he himself has been tortured as he tells Mary in Twigs & Twine & Tasha Banes that "anyone tells you torture is never the answer, they haven't been under the knife."
 * Unusually of Supernatural characters, characters - including Sam and Dean - always refer to Arthur by his last name, with Crowley being the only other character thus far to use his first name. Even Asmodeus generally calls him Ketch. The only time he's called Arthur by any of the main characters is when Dean realizes he is in fact Arthur Ketch at the end of War of the Worlds and pointedly calls him by name a few times. Arthur himself generally appears to just prefer to go by Mr. Ketch or simply Ketch, possibly explaining this.
 * Additionally in War of the Worlds, the Winchesters appear confused when "Alexander" claims to be the twin brother of the Arthur Ketch they knew, suggesting that the Winchesters may have forgotten his first name altogether.
 * Actor David Haydn-Jones also portrayed an unnamed Shapeshifter in the Season 12 episode Twigs & Twine & Tasha Banes.
 * David Haydn-Jones, along with many actors like James Marsters (Don Stark), Charisma Carpenter (Maggie Stark), Mercedes McNab (Lucy), Felicia Day (Charlie Bradbury), Amy Acker (Andrea Barr), Jeffrey Dean Morgan (John Winchester), Ridge Canipe (young Dean Winchester), Donatello Redfield (Keith Szarabajka), Rob Benedict (Chuck Shurley), Julie Benz (Layla Rourke), Amber Benson (Lenore), Harry Groener (Professor Morrison), Chad Lindberg (Ash), and many others, also starred in Buffy the Vampire Slayer and/or Angel, two shows also about supernatural, the former of which has been referenced several times as a television series that exists within the setting of Supernatural.
 * He is the third recurring character to travel to another reality. The others being Claire Novak, Kaia Nieves and Gabriel.