The Joker: Whenever a new Society of Super Villains comes together, The Joker is often excluded. Whilst any decent team-up of bad guys can tolerate a certain amount of back-stabbing and greed (it comes with the territory, after all), the Joker is so absolutely wildly unpredictable that even though he has no powers, most other villains are just flat fucking terrified of him. Summed up best by this quote from Underworld Unleashed:
The Trickster: Oh. Oh, God. Good going, Neron. Pick a guy no one wants to be in the room with. When villains want to scare each other, they tell Joker stories.
On the other hand, Lex Luthor generally makes it a point to invite the Joker to his super-villain team-ups. Granted, he does this for the pragmatic reason that as uncontrollable as the Joker is, it's still better to have him going hog-wild on the heroes than on your super-villain team-up because he thinks you snubbed him. The wrap-up of Infinite Crisis makes this a plot point.
The page image is the Joker breaking up an alliance with the Red Skull, because he realized that the Skull really was a Nazi, and not just wearing a swastika to piss people off. He's a comedian, after all, and the Nazis make mass murder boring. That, and as a proud American, he hates the Nazis.
In the Last Laugh storyline, The Joker is in prison and he is invited to join the Aryan gang. He declines, stating "I may be evil, but you guys are just plain mean." Later on he is disgusted when members of his gang vandalize the Moai on Easter Island.
There was a story line in which the Joker was kicked out of Hell for this reason.
In Death of the Family, this is invoked by The Joker of all people about Captain Boomerang, although mostly as a means of taunting Harley.
The Joker's murder of Sarah Essen-Gordon, Commissioner Gordon's wife, in Batman: No Man's Land is this by the Joker's own standards. After he shoots her, he walks away from the scene frowning, without a single word. He even admits that Commissioner Gordon shooting him in the leg for it (in which he realizes it might be an Ironic Echo to what he did to his daughter Barbara in The Killing Joke) was a lot funnier. If the Joker himself doesn't think something is funny, it's seriously wrong. This is why seeing the Joker stop laughing in his cell at Arkham was one of the creepiest harbingers of the ascendancy of Anton Arcane and his fellow escapees from Hell in Swamp Thing.
As of Dark Nights: Metal, even The Joker found someone so horrifying, he had to team up with Batman to stop him - The Batman Who Laughs. The Joker even directly states that as horrible and painful as the things he planned on doing were in his treachery toward the Legion of Doom... none of it is even half as bad as the utter hell The Batman Who Laughs wants to do. To use Joker's own words; He is... wrong.
Interestingly, in The Dark Knight Returns, the Joker had no qualms having a Neo-Nazi woman who wore swastika pasties on her boobs and butt work for him. Then again, said story was written before most of the examples where he was shown to hate Nazis were (and her appearance in All-Star Batman & Robin, the Boy Wonder, which was written after most examples, was likely a case of Grandfather Clause).
Do not illegally park in handicap spaces on the Joker's watch. He will not be amused. There is nothing funny about it. However, when he's done with you and for the rest of your life you will be allowed to park in handicap spaces, that will have him laughing his head off...
There was a Deathstroke comic in the late '90s wherein Joker was pen pals with the daughter of a nearby town's mayor. The little girl informed Joker that her father was abusive, which led the Joker to escape confinement and arrange an intricate kidnapping plot to save the daughter from her father. Ultimately, the Joker decides the girl is better off with her mom than himself, and the father is jailed.
Joker: I mean, stealing a city blind is something I can admire, but being mean to one’s own daughter, that just makes my blood boil.
Despite the countless atrocities he committed during Emperor Joker, the Joker kills his corrupted version of Jimmy Olsen for killing Superman as a dog.
As far as treason is concerned, in a Justice League of America story, Two-Face found out he was potentially involved with the Qwardians for what would have been a plan to take over Earth. When his famous coin "came up clean" (whole/pure side up) he went to the Justice League: since Batman was out of Gotham, he talked to Green Lantern first. It was a shocker to The Flash when he found Two-Face on the Satellite, and it took one of Hal's energy bubbles around Barry to get the Speedster to listen.
Lobo. For all of the Omnicidal Maniac that he may be (just remember what he did to his homeworld), he will ALWAYS stick to his word. ALWAYS. However, Lobo often only keeps the letter of his word, not the spirit, doing exactly what he promised and nothing more... and God help you if you harm his beloved space dolphins. He was kicked out of Hell and granted immortality so he wouldn't come back. For obvious reasons, Heaven didn't want him either. In fact, he's been rejected by every afterlife there is, including the Nordic afterlife, in which the einherjar fight all day, every day, then feast and party all night, every night, because he's too violent for them to tolerate.
In the last chapter of The Monster Society of Evil, as Mister Mind is being tried, his lawyer, who he knows to be a slick Amoral Attorney, hears of Mister Mind's crimes and tells Mister Mind he hopes he gets the electric chair.
Arkham Asylum: Living Hell has the Joker talking down to a scam-artist corporate executive who got himself judged "Not guilty by reason of insanity." Granted, he's usually crazily giggling and "playing" with cultural values, and bashing executives sounds right up his alley... except he and the plot are completely serious about this. As far as can be told, the issue here is that Warren White is just that big of an asshole. More specifically he says "I've killed people, but I didn't steal their kid's college funds." Hilariously, the Joker isn't the only one who does this in the story. Everyone the scam artist meets in Arkham calls him the "worst man I've ever met". The asylum director (understandable in his case, as Warren robbed him of his pension), Humpty Dumpty, the Joker, and demons from hell—and Humpty is Warren's friend. Oddly enough, White doesn't suffer from this after he truly goes insane and ends up looking like a sharkman after getting locked in Mr. Freeze's cell. The other villains love him and are happy to take advantage of the services he offers unaware that he made a Deal with the Devil that will let him torture them in Hell after they all eventually die.
Batman villain Firefly, a professional arsonist, was working side-by-side with Killer Moth for a short while before Moth realized that his partner was dangerously insane (believing that he could see visions in flames, among other things) and promptly cut all ties with him. Mind, Moth's been on both sides of this trope: when partnered with some other lesser Batman villains in a plan to kidnap Mayor Krol, Commissioner Gordon and Bruce Wayne, he fully intended to let all three die. This caused a rapid breakdown with his "colleagues", who saw it as a first-class ticket to the chair.
In an issue of Gotham City Sirens, Poison Ivy tied up and gagged a nosy coworker who had threatened to reveal her secret identity to the police. Ivy initially planned to kill the woman in order to silence her permanently, but instead released her upon learning that she had a young daughter.
Joker's sidekick Harley Quinn is generally far less violent than Mistah J when left on her own, and never killed "innocent" people in her solo series or the Harley & Ivy stories. She stopped Ivy from executing the C-list heroine Thorn after she attacked them, instead convincing Ivy to leave her hanging Bound and Gagged from a statue. Then again, this had an added Cruel Mercy aspect since Thorn was left thoroughly humiliated after being discovered by the local citizens.
There's also a story from Batman: Black and White where Harley and Ivy rescued a little girl who was being pursued by a sexual predator. They promptly kicked the guy's ass before Batman even had a chance to show up, and the girl was left completely unaware that the women who rescued her were homicidal supervillains.
In Geoff Johns's mid-2000s run of The Flash, Captain Cold violently beats his fellow Rogue Mirror Master for using cocaine. Justified in that he wants to run an efficient ship, and drugged-up partners aren't very conducive to that.
Captain Cold has a record of this: during Identity Crisis (2004), he was noted to have sent flowers to the funeral of the murdered wife of superhero Elongated Man. He's generally been portrayed as viciously mercenary, but strictly professional. It's never—well, rarely—personal. He and the Rogues also halt momentarily during the middle of a robbery when they find out about it. This is partly because they knew that superheroes would be on the rampage after Sue's death, but it was also out of respect for one of their foes.
Cold also mentions breaking Axel (Trickster II's) ribs and docking his take after he caught the kid tying bombs to dogs and homeless people to make snuff films. Axel's a bit of a psychopath, Len tries to keep him... straight... ish.
Mirror Master himself, despite being a merc/assassin (and apparently an on-again off-again cokehead), will not kill children.
Most of the Rogues have some line they won't cross; Gorilla Grodd, Kadabra and the Reverse-Flashes are the exceptions. It's mentioned several times that the other rogues do not consider these homicidal maniacs part of the team.
Trickster: The Rogues never let Kadabra play our little reindeer games. We told each other he was so pompous and throwing his education in our faces. Truth was, he scared the hell out of us. We were a little crazy but jeez, Kadabra was just insane.
When he discovered a female cop he had a one-night stand with had produced a child, Weather Wizard tried to kidnap the infant, intending to sacrifice him and absorb his power. At the last minute, gazing into the baby's eyes, Wizard realized he couldn't bring himself to kill a baby, let alone his own son.
It's one reason the Rogues keep to themselves. When Libra was recruiting other supervillains to join his team, the Rogues turned him down. They just steal stuff—mass murdering of superheroes and civilians isn't their game. (Though this may have to do with Pragmatic Villainy.)
In one Silver Age story the Trickster breaks into a hobby store and weaponizes three of the toys in stock to use in robberies, but goes to the trouble of going in the next day and buying them (instead of just walking off with them while he was there) because he's "not a mean man." Subverted in the same story, combined with Hypocritical Humor, when he comments that, not being a mean man, he wouldn't normally endanger civilians — but it's worth it to distract the Flash, who will save them all anyway.
In another Silver Age story, Captain Cold is offended that Heat Wave served his sentence and was released on parole instead of breaking out — "If there's one thing I hate more than a straight man, it's a crook that pretends to go straight!" To take revenge, he plans to trick him into killingBarry Allen, because Heat Wave will be demoralized and easy to capture once he realizes he murdered an innocent.
In Forever Evil (2013), Cold and the other Rogues raise up a rebellion against the Crime Syndicate after they order the destruction of Central City. The Rogues may have no qualms with conquering the world, but they sure as hell aren't about to kill a bunch of innocent women and children to make it happen.
In the same event, Captain Cold ends up in an Enemy Mine situation where he has to team up with Lex Luthor, Bizarro, Black Adam, and Black Manta. He is visibly disturbed when Black Manta implies that he wants to make sure the members of the Crime Syndicate suffer as much as possible before they die.
Black Manta: Your gun will make them numb. I don't want them to be numb. Captain Cold: You have issues.
Some iterations of The Rogues outright ban members from killing any of the speedsters. Captain Cold loses it when Axel Walker kills Wally West.
Captain Cold: Rule one of The Rogues: Never kill a speedster.
This rule is specifically true during the Countdown to Final Crisis era when Inertia tricks them into killing Bart Allen, causing them to run off in total fear.
Black Adam gets this treatment as well. He may be a murderous Anti-Villain, but he does not take kindly to tyrants and dictators.
The Teen Titans foe Cheshire, in her earliest appearances, did have standards. One issue had her hired by a white racist to murder a black civil rights leader who was pushing to end Apartheid in South Africa, with the added insult of then framing her victim as a Soviet sympathizer. This would effectively tarnish his reputation and lead to other black activists being discredited and killed, thus bringing the civil rights movement to a halt. However, upon killing the activist, Cheshire instead planted the evidence on her own employer, leading to his arrest and execution for treason, as well as the murdered activist becoming a martyr. It was earlier implied that Cheshire's own racial heritage (being half-Vietnamese) led to her obvious discomfort over being hired by white supremacists.
Time went on, however, and Cheshire apparently decided that to get what she wants, maybe she shouldn't have standards. Amongst her later career, she literally detonated a nuke in a Middle Eastern country, manipulated Catman into getting her pregnant, and announced she didn't care that her daughter could be killed for her employer due to said pregnancy as she would still have a child afterwards. The latter incident however seems to have been Retconned to an extent, since she was absolutely devastated and vengeful when her daughter didactually die. Either that or she was bluffing when she said she didn't care about her in the first place. In all honesty, Cheshire's characterization has not been consistent since the Qurac incident. She's either portrayed as having at least some shred of decency left inside her or she's portrayed as incapable of any genuine emotional capability.
She wound up on the wrong end of this with Deathstroke after she sold out her own team to him and was shot in the gut for her troubles, with Wilson making a point of noting just how much traitors disgusted him.
Justice League of America: Lampshaded in Injustice League Unlimited, when Luthor decides on members for his new Injustice Gang. Cheetah objects to recruiting Doctor Light because he was a rapist, but Luthor dismisses this reasoning, stating that "if we want to limit our membership to people of good character...". Later, Cheetah has Dr. Light at her mercy, and evokes this trope... sorta:
Cheetah: Did you think I would work with a rapist without there being consequences?!? Dr. Light: But... you're... you're a murderer... Cheetah [raising her claws to eviscerate him]: Do as I say, not as I do.
In Superman (1939) #416: "The Einstein Connection" by Elliot S! Maggin (a writer who had a definite soft spot for the original Mad ScientistLex Luthor), we learn that one of the few people the brilliant Luthor unabashedly considers a personal hero is Albert Einstein. While fleeing Superman at one point, he passes a body of water and sees somebody drowning. Though grumbling about it, he dives in and rescues the person, even though it costs him his escape, because he just can't'' bring himself to act like an asshole on Einstein's birthday.
In Superboy (1949) issue #85 "The Impossible Mission!", Lex Luthor has a breakdown when he realizes that he has accidentally prevented Superboy from saving President Lincoln's life, since even he knows that Lincoln was a good man.
This became a subplot in Final Crisis with Luthor and Shazam!'s nemesis Dr. Sivana. Originally in league with Libra, both quickly started covertly planning against Libra when they realized the true extent of Darkseid and Libra's plans. Lex decided he rather liked life (as opposed to anti-life) and Sivana said watching his own daughter submit to the Anti-Life Equation was the last straw. Libra's statement that leading the rearguard would grant Lex first place in line in what was implied to be a rape train on Supergirl probably helped to push Lex to find his moral fortitude as well.
In JLA (1997), Luthor physically struck the Joker after the villain openly mocked a group of innocent children who had accidentally been killed during the Injustice Gang's attack on the Justice League. At the end of the story, Lex used the Rock of Ages to resurrect the dead children, with the justification that he could no longer be charged for any crimes if his victims were restored to life. Superman didn't buy this for a second, and told Lex that he knew he did it because he felt bad over the children's deaths, proving that deep down, there is some good in him.
In Forever Evil (2013), Luthor is genuinely distraught after Bizarro is killed.
Captain Cold: Forget that thing. It was just a monster anyway. Lex Luthor: But he was MY monster!
Subverted in The Death of Superman (1961). When Lex Luthor makes public that he has developed a cure for cancer, Superman reflects not even Luthor can be completely evil. Ultimately, though, Luthor proves he is rotten to the core.
Emperor Joker: Given ultimate power, Joker kills Batman in horrific ways after resurrecting him every night, kills everyone associated closely with Batman (Robin, Nightwing, Huntress), eatsall the billion-plus people in China, plans on destroying the entire universe... but when a twisted Jimmy Olsen offers to help the boss by killing Superman (at the time turned into a regular dog), Joker is not pleased.
An Action Comics story had Cheshire assuring a Bound and Gagged hostage that she had zero intention of harming him since he had nothing to do with the actual assassination she was hired to commit. So at least at first, she tried to steer clear of harming innocents during her murders.
In Action Comics #756, an old school villain called Diode the Invincible decides to make a comeback by robbing a bank in a town called Bloomfield. Unfortunately, the town's currently being attacked by a group of vicious terrorists called Doc Omega and the Doomslayers. Unlike Diode, the Doomslayers are a bunch of bloodthirsty psychopaths destroying entire towns for the sake of it and have already killed Bloomfield's resident hero Emerald Don. Diode's understandably disgusted by them, remembering how back in the day people became supervillains for material wealth or to outwit people, and actually helps Superman take the Doomslayers down. This act of standards gets Diode the fame he always wanted and he goes back into retirement content.
Defied in Way of the World. Supergirl breaks super-villain Alphonse Luzano out of jail, hoping he will be willing to help her develop a cure for cancer since a little boy's life depends on it. It turns out that Luzano is rotten to the core and cares for nobody other than himself.
In the final Ms. Tree stories, when the title character is heavily pregnant, there are multiple attempts to kill her. The current head of the Muerta crime family, who now considers the detective family because of her stepson's strong relationship with his niece, confronts the man who commissioned the attempts and tells him that had he known that Tree was the target he would never have agreed to it. However, what really sets him off is Tree's current state; he roars, "You tried to kill a pregnant woman, have you no shame?!" and immediately orders his goons to kill him.
The attempts were because the baby was not the son of Ms. Tree's deceased husband, but of a rebound lover, and therefore eligible for a chunk of inheritance that the would-be murderer wanted all for himself.
Secret Six, a comic about a team of supervillain mercenaries, gets quite a lot of play out of the fact that, while they're all evil, the main characters all have different standards. In one issue Deadshot shoots an escaping slave in the back.
Deadshot: She ran, I shot. I don't know what you want from me. Bane: Murdering slaves? Have you no scruples at all, mercenary?
But Deadshot then gets really pissed off when he finds out the "slave" he shot had actually been set free by her jailer, and the guy who told her she was escaping knew this.
In Watchmen, The Comedian, known for beating and attempting to rape the first Silk Spectre and shooting a pregnant woman who was carrying his child (in the stomach), is horrified when he discovers Ozymandias' plans. Since Comedian was at best a sociopath who, by his own words, saw life as one big Nihilistic joke, another interpretation is that what terrified and upset Comedian was less the lives lost, but more the possibility that Ozymandias' plan would succeed and create a world that he would have no place in.
He is also appalled when Sally insinuates that he would want to commit incest with his daughter.
Sally: Are there no depths you won't sink to? Comedian: Christ, we were just talking! Can't a man talk to his, y'know, his old friend's daughter? I mean, what do you think I am?
Wonder Woman (2006): Foe Dr. T.O. Morrow eventually turns against his own creation Genocide and works to help Wonder Woman defeat it, because he's of Polish ancestry and doesn't want anything to do with a creature who is the personification of genocide.
T.O. Morrow also gets a twisted version of this during JLA (1997), as he informed the League about where a deactivated Amazo was just to shut Professor Ivo up—with the twisted part being he didn't want to help the League too much, so he'd lied and told them they had more time than they did so they'd fight Amazo.
In Batman Incorporated, one member of the blue-collar crime gang Joe Average and the Average Joes gets very annoyed when it's suggested they have a connection to the similar French group Les Stereotypes, who run a child-slavery ring.
Darkseid seems to fall under this. Despite being one of the most evil beings in existence, he does keep his word, such as letting Batman and Supergirl go during The Supergirl from Krypton (2004) arc when Bats threatened to destroy his planet. That said, it didn't stop him from coming down to Earth to royally fuck up Superman, who was not part of the deal. There's also the whole deal with trading sons as a peace treaty. He'll find a loophole, but he usually doesn't betray his deals or promises. Then there was the fact that he threw the villain Sleez, who would later go on to try and make a porn movie with an unwilling Big Barda and Superman, out of Apokolips for being such a creep. (Note that he kicked Sleez out of Apokolips while he was still called Prince Uxas, before he truly ruled the place. If he had, it's doubtful he would have let the creep live.)
In an old Justice League International issue, he allowed the League to leave Apokolips unharmed after he gave his word that they wouldn't be killed. He may be a monster, but at least he honors his promises!
Another Batman example: The Broker narrates an issue to himself in Streets of Gotham. He's a businessman who buys abandoned properties and sells them to super villains for evil lairs (He also has the woman who provides the image for Ineffectual Sympathetic Villain fix the lairs up), he treats his employees well, and works on the standards of privacy and discretion, he also says you need to give to get in Gotham. He also says, that he just sells the things, he doesn't need to know what goes on in them. He mentions how Catwoman, Joker, and Mad Hatter are easy to deal with, but then there's Mr. Zsasz. He's the only man who makes the Broker want to reconsider his job. When he sells Zsasz a meat cutting facility, he sees children in cages begging for him to help them. He takes his money and leaves to go home and try to forget the experience. When Batman demands to know Zsasz's whereabouts, The Broker displays a different set of standards, and how he would never willingly divulge a customers business, no matter how he feels about them. After he's beaten up and Batman takes his records, it's implied that he wanted that to happen, as you have to give in order to get in Gotham; he thought the beating was payment for the information, and he would lose business if people found out he gave out the information without a fight.
In Infinite Crisis, Vandal Savage quits the Society when they attempt to have his daughter Scandal killed for refusing to join up with them, though given that Savage was perfectly okay with arranging for her to be raped to impregnate her with an heir for him, this was probably less about morals and more about pragmatism.
Red Hood and the Outlaws: Arsenal's most cherished memory? Hitting Rock Bottom and trying to fight Killer Croc in order to "suicide by Croc", only to have Croc realize this and tell him to get his act together. A scaled-up beast told Arsenal he was embarrassing, meaning there was nowhere to go but up.
Later Waylon Jones, a.k.a. Killer Croc, becomes his sponsor in his Alcoholics Anonymous Program.
Another Killer Croc moment in the New 52 is in his Villains Month comic, where he savagely hunts down and kills a few crooked cops for the murder of a cop who was nice to him when he was a child. Croc may not hold much love for police, but he knows who his friends are.
One Annual of The Batman Adventures had a story where Scarecrow, under a new identity, has started teaching at a local college and looked to be redeeming himself. Then he found out one of his prized students was and still is a victim of abuse, possibly rape, by her Jerk Jock boyfriend. That was enough to bring back Scarecrow and to show the boyfriend that even someone who's obsessed with other people's fear has limits.
In one Batman storynote Detective Comics #569-570, Catwoman is mind-wiped by The Joker and "convinced" to attack a rich family whose members included a Delicate and Sickly little girl. When Joker tried to attack the girl and harm her in front of her father and older brother, Catwoman broke free of the mind control and attacked him, yelling that she was a thief, not a murderer.
Played for Laughs in Thunderworld #1, which is set in a Lighter and Softer version of the DC universe where the main heroes are the Marvel family. The plot involves Dr. Sivana bringing together an infinite amount of Alternate Universe versions of himself to create a day in which he can defeat Captain Marvel once and for all. One of these versions, it turns out, is a Darker and EdgierJigsaw-like character who went back in time to horrifically butcher Billy Batson before he became Captain Marvel, and wants other versions to kill. The other Sivanas, who are basically Card Carrying Villains, are clearly pretty weirded out.
Jigsaw - Dr. Sivana:Bring them to me! The pretty little heroine, the bright boy! I can't wait to mess them up bad. Regular - Dr. Sivana: Er... quite.
In Convergence: Batman and Robin, Poison Ivy of the pre-Flashpoint Gotham has been making sure the city doesn't starve by growing crops for the population. And she's disgusted that the Penguin would try to make a profit off the food she's been making given the situation Gotham's in.
Telos of all people pulls one on the pre-Flashpoint Joker. After snapping the neck of the clown, Telos proceeds to call him a "vile creature", and a "plague in every timeline".
The Pre-Crisis Crime Syndicate see themselves as this. It's clarified that, while they're lawbreakers, they've never intended to actually hurt anyone and were not killers. This actually plays upon their deaths in Crisis on Infinite Earths where they tried to save Earth-Three, and in Animal Man when Ultraman finds himself utterly disgusted by his alternate world counterpart Overman and tries to stop his rampage.
In Transmetropolitan, "the Beast" is a hopelessly corrupt President Evil, but even he hates "the Smiler" is worried about him becoming president. The Beast, for example, believes he'll be a good president if over 50% of the population is happy. The Smiler only believes he should be president.
Amethyst, Princess of Gemworld: Lady Mordiel is undisputably power-hungry and evil, but she does have some moral standards. When killing a girl with a small fraction of her family blood to absorb her power, she has the family compensated for the loss, and when she later arrives on a battlefield, she has the bodies of her sister's followers be properly buried. She also rejects Eclipso's offer to join him.
In one of the tie-ins to Dark Nights: Death Metal, the Penguin is facing three Dark Multiverse versions of himself and is horrified, partly on aesthetic grounds but also due to his ethical standards. One is a blob monster that consumes everything and everyone; one is gaunt, having apparently traded Oswald's love of good food for unspecified "darker appetites"; and one has a bloodstained mouth and rides a leopard seal, after turning on the penguins.
◊. Ironic, considering he single-handedly created a worse nightmare than Hitler.
