Moments where a character warns an individual that if they kill the murderer, they will be just like him/her in Anime & Manga.
- 7 Seeds: When the Teams of Autumn, Winter, Spring and the rest of Summer A learn that Ango tried to rape Hana, and Hana is currently presumed dead after being sucked into an icy river's whirlpool, Aramaki disarms one of the guys and expresses his wish to kill him, but says right away that he won't... because if he does, he won't be any better than he.
- Baki the Grappler: In New Grappler Baki, Katsumi Orochi gets beaten the hell out of him by an escaped mass murderer named Dorian. When Retsu Kaio returns the returns a beating to him, Katsumi enters the scene and soaks Dorian with gasoline and is about to torch him, when he suddenly stops and says that if set him on fire, he would cease to be a true Karateka, so he walks away. Then he goes: "Actually, that wouldn't bother me at all." Cue the BBQ/delicious subversion.
- In Brave10, Isanami tries to stop Saizo from killing a defeated Kamanosuke when he has him in a Sword over Head situation, despite the fact that Kamanosuke had beat her up, strung her up on a tree, and threatened to rape her because he thought it might make Saizo angrier. Kamanosuke's disappointed that Saizo listens to reason.
- Case Closed: In the climax of the first season episode "The False Kidnapping and Murder Case," Conan uses this trope to convince Akiko to let Mr. Takei live even though he financially ruined her family and drove her father to kill himself, her mother, and her little brother. As Conan points out, Mr. Takei may be a greedy bastard, but he's still the only family his daughter Naoko (the subject of the episode's titular case) has, and if Akiko kills him, she'll be doing the same thing to Naoko that he did to her. Realizing this, Akiko is moved to tears and thanks Conan for stopping her.
- Claymore: Downplayed, Raki tells Clare that if she kills Priscilla and potentially awakens then she’s no different than the Yoma while trying to prevent her from killing the latter.
- Code Geass: Suzaku Kururugi comes within an inch of using drugs to interrogate Kallen. He only stops because he believes his final words to her, "You will follow my orders," is what Lelouch does with Geass.
- Daimos: Kazuya says that if Sayuri kills a wounded Baam-seijin solder who can't fight back, she will never be able to go back from it.Kazuya: "Listen, listen carefully... If you had killed that Baam alien, you would be filled with regrets for as long as you live. We're humans, even if our enemy is like a beast, we won't turn into beasts ourselves!"
- In Death Note, Ryuk tells Light that if he kills all the bad people in the world, then he himself will be the only bad person left. Light promptly deflects the suggestion and proclaims his desire to be the God of a new, perfect world.
- Digimon:
- Subverted in Digimon Data Squad. Marcus and Shine Greymon have defeated Kurata's One-Winged Angel form, and effectively have him completely beaten and begging for mercy. Not a single one of Marcus' allies pull this trope on him, instead actually encouraging him to kill him! What avoids making this a Start of Darkness is that Kurata is really that much of an evil bastard.
- Deconstructed in Digimon Adventure 02. Evil Digimon are released into the human world and Yolei and Cody are horrified when their Digimon are forced to kill them. It's quickly pointed out that the evil Digimon had no problems about killing innocent people and they would have killed Yolei and Cody had their Digimon not saved them. They tried to send them back to the Digital World but no other options were available.
- Played straight in Digimon Tamers. Jeri stops Gallantmon from landing the killing blow on Beelzemon because she knows that won't bring back her partner.
- Dragon Ball:
- When Vegeta is finally taken down by Son Goku and his True Companions, he tries to crawl back to his space pod and make his escape. Kuririn grabs Yajirobe's katana, intending to put the heavily wounded Vegeta down once and for all. But Goku stops Kuririn and asks him to let Vegeta live. In some versions of the English dub, he justifies this by telling Kuririn that killing Vegeta in cold blood will make them just as bad as he is. The original story averts this, however: Goku doesn't care about the morals of the situation, he only wants Vegeta to live so he can fight him again, even though he knows this potentially puts the Earth at tremendous risk. Goku even admits this is a selfish request.
- Subverted. Goku decides not to finish off Freeza after defeating him in battle, which is an extremely hard decision for him to make. He even gives him some of his energy. However, when Freeza uses the donated energy to attack Goku one last time, Goku changes his mind and goes for the killing blow after all. Only later do we find out that Freeza survived it. None of this is because of any moral high-ground but more because of a combination of that he no longer found Freeza worth fighting and pragmatism to escape the exploding planet Namek.
- Fullmetal Alchemist:
- Several characters attempt to keep Roy from killing Envy. At least Riza has no qualms about executing him and offers to do it in his place, but they all agree on the detail that subjecting him to horrible torture first is taking it a step too far. Scar adds an extra spin by pointing out that if Roy goes through with it, he'll be just like him. For added nuance, the reason for this isn't because he was going to horribly torture him, since at that point it would be near impossible to hurt Envy without killing him anyway, but because of the reasons for doing so. Roy was going to kill him for personal reasons like vengeance instead of duty, and since his goal was to become leader of the country, he simply can't afford to become the sort of person ruled by his emotions, and specially by bad ones like anger and revenge. If he does, the horrifying mental toll this whole deal is taking on Roy will send him straight into the He Who Fights Monsters path.
- Earlier, when Winry discovers that Scar was the one who killed her parents, she picks up a dropped gun and is on the verge of shooting him for it. Scar states outright that she has every right to do so, but Ed vehemently protests against doing so, talking her down while Al chases Scar off.Winry: But that man... You said that he was the one who killed my mom and dad. He tried to kill you and Al too, Ed. But I couldn't... why not?
Ed: Remember in Rush Valley? You delivered that baby, you saved two lives. And you gave me an arm, and a leg, to replace the ones I lost. It's your hands. They weren't meant to kill. They're meant to give life. That's why. - In Fullmetal Alchemist (2003), Ed spends every fight with Scar telling him that the slaughter of alchemists and Amestrian troops isn't the answer, and that he must be brought to justice for those crimes as well as killing Tucker's daughter. Each time, Scar shows Ed more and more horrible deeds he's avenging, which Ed always brushes aside. Eventually, upon confronting Scar in Lior when Scar's about to secretly evacuate the city of civilians, lure in the Amestrian army, and kill all of them to make the Philosopher's Stone, Scar pounds into Ed that Lior was purposely sabotaged by Amestris, Amstrian troops have been brutalizing the city, alchemists are killing civilians in the streets right now, and the girl Ed thought he saved in his previous visit (standing right in front of him, unable to speak due to mental trauma) was raped and used as a tool to create even more violence, and that all of it was partly Ed's fault. Ed still refuses to condone what Scar is doing, but when Scar orders him to get out of Dodge with the refugees, Ed shuts up and meekly complies.
- In the Full Metal Panic! novels, this is pretty much what Tessa tells Sousuke during the Behemoth arc, when he decides that shooting Takuma would be an effective action to take. "It would be the most logical and secure route, but we can't go about it that way," she said as though trying to convince herself. "If we were to kill him, we would be no better than them. Our organization would lose all meaning." Sousuke is slightly skeptical about this (seeing how Kalinin, his adoptive father whom he was always taking orders from, undoubtedly would have done what he was about to do), but nevertheless follows orders, seeing how he doesn't really care either way. Of course, later on, the fact that she let Takuma live led to a huge amount of destruction...
- In The Garden of Sinners, Mikiya doesn't want Shiki to kill Lio, despite him being a crazy cannibalistic superman, because he feels that Shiki isn't and shouldn't become a murderer. At first she defers to his wishes. Then Lio stabs Mikiya in the eye, seemingly killing him. An enraged Shiki then kills him anyway. Mikiya, after he wakes up, is somewhat annoyed, but seeing that Shiki's murderous side remains under control, says that he'll get over it.
- The titular character in Ginga Densetsu Weed. So much, especially during the final episode in which Weed has the chance to finally avenge his fallen comrades by killing Hougen once and for all. His father intervenes and is about to kill him when Weed pushes him out of the way, claiming that his father would be no better than Hougen if he'd killed him. There's quite a few examples in this series, suffice to say.
- Goblin Slayer: Pointedly not the case here. When a character tries to use this line on the titular Slayer, his response is basically "Good, I want to be the monster that goblins are to me and every other undefended village that they prey on".
- GTO: The Early Years: Eikichi has to be physically prevented from beating an enemy to death at least twice:
- In Eikichi's battle with Okubo, Saejima has to stop him from killing Okubo, because he doesn't want his friend to become a killer. Okubo seizes the opportunity to stab Eikichi in the arm, but is knocked out cold with a massive uppercut.
- After Nakagaki shoots Natsu, Eikichi beats him to a bloody pulp and only stops when Ryuji grabs him from behind.
- In JoJo's Bizarre Adventure: Diamond is Unbreakable, Angelo invokes this against Josuke in an attempt to save his hide. As it turns out, Josuke had no intention of killing him anyway, with the implication that death was too lenient for him, and instead permanently merges him into a rock.
- Used in Omamori Himari. Made especially justified by the fact that the girl that Shizuku wanted to kill wasn't the man who killed her family. The girl was the great-granddaughter of the man who genocided the Mizuki race, and happened to be completely ignorant of her long-deceased ancestor's crimes.
- Mobile Suit Gundam 00:
- Saji Crossroad's justification for not pulling the trigger on Setsuna F Seiei in , although it remains to be seen how long he can hold on to his convictions.
- Louise is warned that her desire to kill Nena Trinity to avenge her family's death will make her no better. Indeed, when she actually DOES kill Nena, she becomes just as psychotic as she was. Thanks to The Power of Love in the final episode, she manages to get better though.
- Naruto Shippuden, has Pain saying this to Naruto, and he should know, he's already gone down that road.
- Turns up in the climax of the final episode of Noir. Not that that stops the protagonists from killing off Altena anyway.
- Persona 4: The Animation: In episode 23, the Investigation Team argues about throwing Namatame into the TV World and leaving him to die, like he did to most of them and Nanako. Yu, in full Tranquil Fury mode, very nearly does so, but stops at the last second and makes this argument, promptly silencing those in favor of doing so and making them see sense.
- This is found a lot in Rave Master the reason Haru gives for not wanting to kill his enemies is because he'll be just as bad as them. He didn't actually kill anyone besides Doryo.
- In the second season finale of Rozen Maiden, Jun utters the line when Shinku was about to kill Barasuishou. Bad move. She uses the chance to defeat Shinku.
- In the Story Within a Story of the music video arc of Skip Beat!, Kyoko's character, an angel, is forced to murder Sho's character, a demon, in order to protect her friend. This fills Kyoko's character with such guilt and rage that she becomes like a demon herself.
- Subverted in The Testament of Sister New Devil. Basara uses this reasoning to stop Mio from finishing off Zolgia, who murdered her foster parents and took Maria's mother hostage as leverage to get the powers Mio inherited from her father the Demon Lord Wilbert. Actually, Basara had promised Lars in exchange for his help rescuing Mio that he would get to kill Zolgia, since Mio's foster parents had also run the orphanage where Lars grew up.
- Vash, the Martial Pacifist hero of Trigun, goes through the tortures of the damned rather than kill anyone specifically to avoid this trope. Accordingly, the entire last half has the Big Bad sending his suicidal followers to try and forcefully invoke it. Despite the last of them finally succeeding in his mission, it is, in the end, averted.
