History Main / ThouShaltNotKill

* Franchise/{{Superman}} has taken a solemn vow ''never'' to kill. It's strongly implied -- and outright used in ''ComicBook/WhateverHappenedToTheManOfTomorrow'' -- that he believes that he should give up being Superman if he takes a life. (He cannot kill himself, since his oath applies to himself as well. This was shown in a number of Bronze Age stories, including one where he is caught in a hallucination that supposedly shows the future and realizes that since it shows him killing himself, it must be false.)

* When ''ComicBook/TheFLash'' thought he killed Godspeed, whom he'd been insisting that real heroes never kill:

This is TruthInTelevision. In general, there are very few humans who can stand the thought of ''truly'' ending the life of another human without military training. The military has developed many studies over the years to evolve the best training curriculum to dehumanize the "enemy" and enable their soldiers to kill enemy soldiers. Even then, when a soldier is tasked with actually shooting a bullet that would end the life of another human being...many would rather intentionally miss. It is this (strength, in the case of all human life, but weakness in the case of human life with an opposing ideology) that makes modern militaries attempt to make the enemy soldiers appear as "unhuman" as possible. Otherwise, despite how some may make boasts to the contrary, in truth most people - including law enforcement - are loath to take a life unless absolutely necessary in the course of self-defence or the protection of others.

* In ''Franchise/StarWars'', the Jedi have compassion for all living things, and so they extremely dislike having to kill someone or something. However, they realize that it is sometimes necessary.

* ''Manga/FullmetalAlchemist'': Main character Edward Elric refuses to kill to achieve his goals, even Homunculi. Still doesn't make him any less {{Badass}} by any stretch of the imagination. [[spoiler:Just look what he did to Pride. In fact, the closest he comes to killing anyone is when he punches through Father's chest after regaining his arm, and even then, he didn't actually die...instead, what happened to him was [[FateWorseThanDeath far worse]]]].

* ''Film/ButchCassidyAndTheSundanceKid''. Butch Cassidy, the tough, notorious, wildly-successful, train-looting, bank-robbing, gun-waving, {{badass}} outlaw, when faced with the prospect of a shootout, lamely admits to the Sundance Kid that he had never killed a man in his life. It's almost painful to hear Butch pleading with the bandits to go away so that he won't have to defend himself.

* In ''Literature/FromTheNewWorld'', Squealer is not granted the death penalty for his crimes. Instead, he is sentenced to [[FateWorseThanDeath an eternity of suffering]]. He is then tortured and consumed alive by a special parasite, only for his cells to be regenerated simultaneously, allowing for eternal torture.

* In Literature/FromTheNewWorld, Squealer is not granted the dealth penalty for his crimes. Instead, he is sentenced to an eternity of suffering. He is then tortured and consumed alive by a special parasite, only for his cells to be regenerated simultaneously, allowing for eternal torture.

** This is the hallmark of [[XMenFilmSeries/ProfessorCharlesFrancisXavier Professor X]] for most of the X-Men hexalogy;[[note]]the original trilogy and the First Class trilogy[[/note]] he detests violence and firmly objects to the notion that deadly force is required to subdue evildoers. A grey area occurs in ''Film/XMenFirstClass'', where Magneto's insatiable desire for revenge corners Charles into a moral bind--[[spoiler:if he releases Sebastian Shaw from his psychic grip, then Shaw will eliminate Erik, but if he maintains the mental hold, then Magneto will kill their target, and Xavier becomes an accessory to murder; Charles opts for the latter]]. In ''Film/XMenApocalypse'', he breaks his one inviolable rule when his own life, the lives of his team and billions of others are at stake: [[spoiler:he's unable to take down Apocalypse on his lonesome, so he commands Jean Grey to immolate his adversary with her Phoenix Force]].

* ''Manga/OnePiece'' plays with this trope; the main character, Luffy, will not kill anyone, but it's not out of niceness. [[CruelMercy He just thinks it's a worse punishment for them to live, and watch their dreams get shot down in flames by him and his crew]].

* ''Film/XMen'':

** This is the hallmark of [[XMenFilmSeries/ProfessorCharlesFrancisXavier Professor X]] for most of the X-Men hexalogy;[[note]]the original trilogy and the First Class trilogy[[/note]] he detests violence and firmly objects to the notion that deadly force is required to subdue evildoers. A grey area occurs in ''Film/XMenFirstClass'', where Magneto's insatiable desire for revenge had placed Charles in a moral bind--[[spoiler:if he releases Sebastian Shaw from his psychic grip, then Shaw will eliminate Erik, but if he maintains the mental hold, then Magneto will kill their target, and Xavier becomes an accessory to murder; Charles opts for the latter]]. In ''Film/XMenApocalypse'', he breaks his one inviolable rule when his own life, the lives of his team and billions of others are at stake: [[spoiler:he's unable to take down Apocalypse on his lonesome, so he commands Jean Grey to immolate his adversary with her Phoenix Force]].

* Subverted in a rather surprisingly brutal way in the movie ''Film/{{Darkman}}''. The protaganist has caught the bad guy from falling to his doom by the pantleg. The bad guys starts into a typical "You can't kill me, you're the good guy..." speech, [[spoiler: and unwisely ends it with the line "you couldn't live with yourself." The protagonist, who by this point has been burned beyond recognition, left for dead surgically altered, and has already killed ''every'' one of his hired thugs(Which he knew about!) promptly lets go of the bad guy, letting him fall to his death, replying "I've had to learn to live with a lot of things."]]

** During [[https://www.youtube.com/watch?v=wAg2m5UlBYw a non-canon fight]] between Batman and {{Deadpool}}, Deadpool mocks that Batman can't beat him because he can't be killed. Batman snaps, "I'm ''counting'' on that." Cue Batmobile twin rocket launchers turning Deadpool into LudicrousGibs. After Bats leaves with Catwoman, Deadpool's head is mildly annoyed.

** When it comes to ultimately dealing with the BigBad, [[spoiler:KarmicDeath it does the trick]].
** The magical world apparently has extremely dim views about killing, since murder can literally ''rip your soul in half''.

* The wisdom of this trope is called into question by [[spoiler: a ''different'' Robin, Jason Todd]] in ''WesternAnimation/UnderTheRedHood'' centered around The Joker once again.

-->'''Joker:''' "Oh Batman, if you had the guts for ''that'' kind of fun you would've done it years ago. I, on the other hand..." (proceeds to attack)

** Though it's often overlooked, during his final fight with Doomsday at the end of "ComicBook/TheDeathOfSuperman" storyline, he was trying to kill him. If he hadn't, Doomsday likely would've destroyed Metropolis and everyone in it. It probably helps that Doomsday's mind was read a couple of times in the story, and was revealed to be nothing but rage and bloodlust. This was followed up in ''Hunter Prey'', as Superman, after finding out that Doomsday was now far more powerful than himself, and constantly growing in might, he could come up with no other available options than letting Waverider exile the beast to the end of the universe, to let entropy consume it. Doomsday was later rescued by Brainiac, keeps coming back after being killed, and heals all other injuries instantly, so breaking his neck has the same effect as knocking a regular villain out, which, in combination with being more than Superman can handle upfront, is the reason why he can be the exception.

** There were at least two [[UsefulNotes/TheBronzeAgeOfComicBooks Bronze Age]] stories in which criminals tricked Superman into believing he had accidentally killed someone, so that he would hang up his cape and stop fighting crime (in one, they tricked him into thinking he had accidentally killed Lana!).

-->'''Salvatore Morone''': "From this height, the fall wouldn't kill me."

** Nineties anti-hero Comicbook/{{Cable}} (an amazingly powerful telekinetic infected by a nano-technological virus who used huge guns ... no, really) had no qualms about killing and invariably racked up a huge body county every issue. Always without any ramifications. And in his most recent shared series, he came across as the good partner. The other guy was {{Deadpool}}.
** A move towards this has actually become one of the significant driving arcs for Comicbook/{{X 23}}: She was bred and trained from birth to be the perfect assassin, and even after first joining the X-Men she was a ruthless killer who may have been even ''more'' efficient at it than Wolverine, with Matthew Risman telling her she was "bred for murder." However X herself hated what she was, and has increasingly tried to avoid resorting to lethal force. By the time of ''Comicbook/AllNewWolverine'' she has sworn off killing entirely.