No matter how evil the villains are, the good guys can't just kill them: heroes are supposed to be better than that. They need to stay pure and noble (or innocent); role models, exemplars of solving their problems without resorting to bloodshed. If they take another person's life, no matter how justified, they will lose their moral edge.
But when the villains are just arrested and hauled away by the police, this isn't satisfying. For one, they have a tendency to escape. For another, the mundane workings of the criminal justice system seem woefully inadequate to hold or to punish a really evil villain. We, the viewers, want to see real justice administered, and we don't trust human hands (or at least not heroic human hands) to administer it.
So, the writers arrange for the villain to die in a manner that is completely his own fault. Or, at least, obviously not the hero's. If he dies right in the act of attempting to kill the hero, this gives a particularly nice karmic zing. If he attacks after being defeated and then spared by the hero, this is one of the rare circumstances where the hero can dispatch the villain personally and still come across as blameless.
Note that this only applies if the villain is clearly human, or the show universe's nearest equivalent. If they change into some kind of monster, they are no longer protected by this trope: the hero might hesitate to kill another human, but a mutated, horrendous beast is fair game — doubly so when the villain took this form for the sole purpose of murdering the hero. The trope may still apply if the villain's inhuman nature somehow allows him to escape justice at the mortal heroes' hands; in such a case, their doom would come from a completely unexpected quarter, such as previously abused minions finding and shattering the villain's Soul Jar to avenge themselves, without any involvement from the heroes whatsoever (and the minions possibly not even pulling a HeelFace Turn). And if a Karma Houdini finally becomes the receiving end of this trope, this is Karma Houdini Warranty.
It's more common in Western markets, as a result of heavy censorship and the general reluctance among writers to feature their character (usually in a show with a younger Demographic) doing such acts as killing, especially if they're underage. Occasionally known by the older demographic as "getting one's comeuppance." Given that there is a certain charm to Self Disposing Villainy, this trope can show up in works that allow the hero to kill people; it's just that it's much more common for it to show up in situations where the hero has a no-kill policy for one reason or another.
Compare Asshole Victim, Hoist by His Own Petard and A Taste of Their Own Medicine. See also Cruel Mercy. The Dog Shot First usually involves this. The Killer Becomes the Killed is a Crime and Punishment Series variant.
As a Death Trope, all Spoilers will be unmarked ahead. Beware.
- Anime & Manga
- Comic Books
- Fan Works
- Live-Action TV
- Video Games
- Western Animation
- The vocaloid songs series The Seven Deadly Sins by mothy has plenty of this:
- In Evil Food Eater Conchita, the titular character eats herself.
- In The Madness of Duke Venomania, the duke is killed by a man dressed like a woman.
- In Judgement Of Corruption, Marlon is sent to Hell with the exact same words he gave criminals.
- In Princess Sleep-Bringer, Margarita commits suicide by drinking the poison she had given to everyone.
- Riliane (Daughter of Evil), Kayo (Tailorshop on Enbizaka) and Nemesis (Muzzle of Nemesis) are the only ones who avert this trope. Kayo is simply arrested and put to death, Riliane's situation is... complicated, and Nemesis is the one who's dishing OUT karma in her song.
- The official music video for Foster the People's "Best Friend" revolves around an envy-maddened supermodel wannabe, who discovers she can steal desired traits from other supermodels by swallowing them whole and alive is ultimately killed when she fails to successfully barf up the dress of her latest kill, choking to death due to it lodging in her throat.
- The Adventure Zone: Balance: After the "Vogue Elves" have sustained their undeath for untold years by feeding off the pain and misery of others, Lydia dies of despair when Edward is defeated.
- The Terran Empire setting for Star Hero isn't a no-kill setting, but manages to sneak this in anyway. One of the later Emperors spent a good chunk of his reign giving people a reason to want him dead. He knows this, so among other precautions his bedroom is heavily armored and has a voiceprint lock on the only door. He also changes the door code daily, to keep assassins from using a recording to get in.
In 2663 he forgot the code overnight and could not get out of his bedroom. His guardian robots refused to allow anyone to approach the door with drills or cutting torches, and the Emperor died of thirst and starvation in his own room.
- In the backlore for Ravenloft, Doctor Rudolph van Richten only became a Hunter of Monsters after a tribe of Vistani kidnapped his son and sold him to the vampire Baron Metis to become that vampire's Bride note . They kidnapped his son because one of their own was mortally wounded attempting to kidnap somebody else's son to be the Baron's Bride instead and Doctor van Richten wasn't able to keep their tribesman from dying. When van Richten caught them, they taunted him about what they had done, confident that their fearsome reputation as masters of curses would keep them safe. Instead, the heartbroken father cursed them and the Dark Powers answered, unleashing a horde of murderous zombies on the Vistani and wiping the tribe out. The only survivor spent years being chased from place to place by undead seeking to fulfill van Richten's curse and kill him.
- Ace Attorney:
- Manfred Von Karma, though it's debatable whether he was sent to life in prison or was given capital punishment. Phoenix does a turnabout and proves that Von Karma shot and killed Edgeworth's father when Edgeworth threw a gun and triggered the bullet to hit him. Von Karma goes through a long series of events to get Edgeworth guilty of either that murder, or the murder of another man. By wanting Edgeworth to believe he had murdered his own father, he helped lead to his downfall.
- In Ace Attorney Investigations: Miles Edgeworth 2, one killer fled the country for a few years after successfully testifying in a trial against the man he was framing. Eighteen years later he admits his crime happily now that the statute of limitations is up - but by fleeing the country while still technically a suspect all those years ago, he wound up extending the statute on the case, giving him a one-way ticket to prison once he confessed.
- Ace Attorney Investigations features Manny Coachen getting murdered by the leader of a smuggling ring. Said leader ordered Coachen to kill a witness to the ring's dealings 10 years prior. The motive as to why said ringleader murdered Coachen? Because he was a witness too. Well, technically there were multiple motives but this is one of the main ones.
- The victim in case 3 of the first game actually dies by being Impaled with Extreme Prejudice on some metal fence spikes. As revealed during the trial, the woman whom he tried to kill and who pushed him on the spikes witnessed her boyfriend being accidentally killed by the victim in the exact same manner on the same spikes.
- Fate/stay night has this happen oh-so-satisfyingly to Shinji Matou in two of the three routes. In Fate it takes the form of fleeing the scene of Rider's annihilation at the hands of Saber and Excalibur only to run into Ilya and Berserker. In Heaven's Feel he meets his end at the hands of his own sister Sakura of all people when he tries to blackmail her into a position where he can rape her.
- Nine Hours, Nine Persons, Nine Doors: 9 years ago, Ace threw Akane into the incinerator for his research about curing his own prosopagnosia. In the "Safe" ending, he gets his comeuppance in the very same room by being burned alive.
- During Arcueid's route in Tsukihime, a combination of factors make Shiki go briefly insane and sexually assault a drastically-weakened Arcueid. The player can choose whether Shiki gets a hold of himself, or gives in to his desire and rapes her. The correct choice, naturally, is to stop; the next night, Arcueid has another spasm and tries to drink Shiki's blood... and hesitates, long enough for Ciel to come to Shiki's rescue. If Shiki gave in to his dark side and raped her, on the other hand, Arcueid doesn't hold back, either...
- Danganronpa has a good number of these, as to be expected. Most of them are execution scenes, but some of the murders count as well.
- The Accuser: That's what Dr. Pirot gets for helping a serial killer to survive execution.
- RWBY: When Ruby fights Roman and Neo on top of a flying battleship, she's knocked down and hangs from the side of the ship helplessly. Neo leans on her unopened weaponised parasol to kick Ruby off the ship, allowing Ruby to grab the parasol's catch; it opens, catches the wind and blows Neo off the ship, while Ruby regains her footing. Roman then brutally beats Ruby to the ground, ranting about her misguided idealism in a savage world where most huntsmen die young. His heightened negativity attracts the negativity-sensing Monsters of Grimm, and one swallows him whole just as he's stating that the only thing that matters is survival skill.
- Happy Tree Friends: In the episode 'Sea What I Found', Lifty and Shifty steal Disco Bear's golden submarine in order to steal treasure from Lumpy and Russel, which they successfully do. When the submarine goes over an underwater volcano, it begins to grow in temperature, and fall apart, causing Lifty to get stuck under some debris. Instead of helping his brother, Shifty instead takes the gold and treasure he was wearing for himself and leaves Lifty to die. However, after having to force himself to walk due to his feet sticking to the hot floor, ripping off the bottoms of his feet in the process, he finds himself too weighed down by all the gold he is carrying to crawl through the porthole leading to the ladder so he can climb up. And then, the gold reaches its melting point, causing him to get rapidly covered by boiling hot molten gold, resulting in him getting turned into a solid gold statue. As for Lifty, he survives the submarine exploding with fairly minor injuries, only to see his brother's golden remains. Rather than swim to safety, he instead tries to drag his golden brother back to shore, entirely out of greed, mind you, only to get his arm stuck, resulting in him drowning.
- Survival of the Fittest:
- Jack O'Connor cheats in a Ten Paces and Turn duel, only to find his opponent (Adam Dodd) had been walking down a slope (something of a Deus ex Machina). Jack shooting early allows Adam time to find his aim and fatally wound Jack to win the fight and v1. This also apparently makes the fact that Adam was planning on cheating okay simply because Jack tried it earlier.
- Laeil Burbank's first kill (and, in fact, first scene in V3) involves her torturing her helpless cousin, leaving him begging for mercy before killing. Of course, it's only fitting that her death involves a helpless Laeil getting horribly tortured and left to die, also begging for mercy. It's also a rare case of a Karmic Death where one can feel sympathy for the victim, mostly because her cousin was a dickweed, she had something of a temporary Morality Pet in both Jimmy Trejo and Eddie Sullivan, and the guy who tortured her, JR Rizzolo, was a monster. And there's also her tragic Back Story...
- In another example, rapist and literal lady-killer Adam Reeves has a two-for-one when he gets his nuts blown off right before his death at the hands of Alexis Machina.
- Dragon Ball Z Abridged: Through the entire show, Super Kami Guru has been a bigger asshole than even the villains of the arc, to the point he decided to die just because dying at that exact moment would be a giant dick move. After it's all said and done, and he's revived but dying of old age, he decides to make one final Deathbed Confession that the giant drought he had blamed on the Albino Namekians was actually his fault, thus the latter were slaughtered for nothing. Then, he gurgles one last breath as everyone is too shocked to respond... only to realize he isn't actually dying, and is fine. At least until the enraged Namekians present tear him apart so viciously even Vegeta, who was watching the whole affair, is disturbed.