One of the occupational hazards of being a Hunter of Monsters involves the death of your friends and family out of vengeance from the monsters you hunt. But sometimes the monsters don't just kill your loved ones. No, sometimes they get extra sadistic and turn them into one of their own. This puts the protagonist in the awful position of having to kill someone they truly loved.
Expect this trope to crop up in Vampire Fiction, almost always when the monsters are Always Chaotic Evil. Usually averted with the Friendly Neighborhood Vampire. This situation can also crop up with other monsters, the most common variations being werewolves and zombies.
Subtrope of Shoot the Dog. Likely to be Dirty Business and to lead to I Let Gwen Stacy Die. See also And Then John Was a Zombie. May be a case of Van Helsing Hate Crimes when the monsters are not Always Chaotic Evil. Related to Transhuman Treachery, as this is what the newly turned are feared to commit. Often the only "good" way What Happened to Mommy? can end up. Frequently a Tear Jerker.
See also I Cannot Self-Terminate, Mercy Kill, and Mercy Kill Arrangement. Sub-Trope of Kill the Ones You Love and Tragic Monster. Compare and contrast Supporting the Monster Loved One, which is this trope's alternative. Not to be confused with stalking the loved one.
As this is a Death Trope, unmarked spoilers abound. Beware.
- Fate/Zero shows us the consequences of not doing it: after drinking a potion that transformed her in a vampire, Kiritsugu's childhood friend Shirley begged Kiritsugu to kill her while she was still capable of resisting her instincts, but when Kiritsugu couldn't go through it (opting instead to ask the local priest for counsel) she caused a vampire outbreak that claimed everyone on the island but Kiritsugu and his father. The experience, including the Church and the Mage Association killing all the vampires and burning down the place and having to kill his own father for experimenting on vampirism, was Kiritsugu's Cynicism Catalyst: since then Kiritsugu never hesitated to pull the trigger whenever necessary, and when he got to choose between shooting down a plane with his mother surrogate and a horde of ghouls on it and risking it to cause another vampire outbreak he immediately shot down the plane.
- In Hellsing, Integra is instructed to put down her subordinates-turned-ghouls herself, since she was their leader and thus their being defeated and transformed is her responsibility.
- Magical Girl Lyrical Nanoha A's ends with everyone defeating the Self-Defense Program of Reinforce, the former Book of Darkness. She's grateful, but the next day informs them that they have to finish the job with her too or else her programming will be forced to regenerate the SDP. Nanoha and Fate do because it would be too cruel to make Hayate do so.
- Subverted in Parasyte—Shinichi tries to do this to the Parasite who killed/infested his mom but freezes up at the critical moment. Mamoru Uda and Jaw kill her instead, with the former arguing that Shinichi shouldn't have to be the one to do it.
- Puella Magi Madoka Magica:
- Kyouko is forced to kill Sayaka, who turned into a Witch.
- In the previous iteration, it's Homura who must Mercy Kill Madoka. This pushes her into Antiherodom.
- Darkly Invoked too by Mami in the previous iteration, rather than seeing her other mentee go Sayaka's path, she would rather kill them. Madoka stopped her from killing Homura... by shooting her first.
- In an inversion, Rosario + Vampire has the vampiric Moka nearly beating the human Tsukune to death because he had become a ghoul that was dangerous to everyone around him. She considered it her responsibility to finish him because she was the one who caused the transformation.
- Tokyo Ghoul :Re: After encountering his Not Quite Dead Sidekick as a deranged half-ghoul, Houji makes the difficult decision to attempt to put down his former subordinate himself. It......does not end well, with Takizawa slaughtering the entire squad in a rage. He kills Houji via decapitation, before strangling Akira while demanding to know why they would try to kill him when he just wanted to help them.
- Caballistics, Inc.: Hannah Chapter reveals to a psychic vampire that before becoming an Occult Detective she was once involved with a woman who turned into a zombie, forcing Hannah to blow her head off. She turns off her com so that Lawrence (her closest friend) can't hear this.
- Cassie Hack in Hack/Slash had to do this to her deranged undead mother. It ended up as a recurring Flashback Nightmare for her. She's actually done it three times so far. Delilah Hack just doesn't seem to want to stay dead.
- The last act of Dmitri Mishkin, in House of Mystery's "I... Vampire" series, was to stake his own mother. Kind of an odd encounter, given that she'd been turned when Dmitri was a small boy and he'd been hunting her for decades, so his mom looks a good fifty years younger than he does.
- New Avengers (2015): A future version of Hulkling, called King Hulk, travels back in time with what's left of the Avengers to stop Teddy's husband before he's possessed by an evil warlock called Mor-i-Dun. By the time they show up, it's apparently too late, and Future Teddy advises Present Teddy to kill Wiccan before Mor-i-Dun can go on an omnicidal rampage with all of Wiccan's powers. Present Teddy says "screw that!", and manages to encourage Billy into driving the warlock out himself.
- In one Spider-Man story, Morbius the Living Vampire is confronted by his once human ex-fiancée Martine, now a real vampire. During the fight that follows, Spider-Man is unable to go through with staking her because he reasons she used to be a living human being. It is Morbius who then throws Martine onto the stake Spider-Man is holding, afterwards explaining that the real Martine died a long time ago.
- In the tie-in comic The Strain: Mister Quinlan - Vampire Hunter detailing the backstory of Mr. Quinlan, he was part of a slave ludus during the Roman Empire. When the Master arrives and turns all other slaves except Bruk into vampires, forcing Quinlan and Bruk to fight their way out against their former friends. Bruk is infected during the struggle and request his friend to decapitate him before he can become a monster himself.
- In Marvel's The Tomb of Dracula, Drac is clockwork predictable with this trope. Virtually no one outside the 'Bridge Crew' was taken prisoner without being turned.
- Defied in X-Men, where the team flat out rejected this as an option after Jubilee was turned, although Blade tried to convince them there wasn't any other. She handled herself okay until she was eventually cured.
- The Heroes/Twilight crossover "Dark Days" features a low-key version of this when the Haitian is revealed to have been turned into a vampire as part of Victoria and Adam’s plans. While Elle wasn’t a close friend of his, she was at least a professional acquaintance, and accepts the Haitian’s request that she kill him after Adam and Victoria have been dealt with as he doesn’t want to exist like that.
- In the Angel/The Hunger Games fic Demon's Games, the final battle sees Katniss forced to stake the now-vampire Prim, tearfully accepting that the sister she loved has gone forever before she hits the Despair Event Horizon and has to be saved from a burning building by Peeta.
- Peripherally applies in TorontoBatFan's Let Me In fic Eternally Bonded, when Owen and Abby essentially kill a woman who was attacked by Abby's vampire uncle Jebediah (they burn down the morgue her body was being kept in before she can 'wake up' as a vampire). They don't know the dead woman themselves, but she was married to a friend of Owen's grandfather Oscar, who has given Owen and Abby a safe place to stay since they left Owen's apartment building.
- Done with a twist in The Return when one character is forced to shoot her sister who has been turned into a demon so that she can be given an Emergency Transformation to save her.
- In Stephen King's Night of the Living Dead (1968) fanfic story The Reach, the inhabitants of a small New England island off the coast of Massachusetts cooperate to rid their island of zombies and to prevent the local graveyard from spawning new ones. When the strain gets to be too much for one old man, he begins suffering a heart attack. Rather than risk dying and coming back as a zombie, he tells his sons that he's going to recite the Lord's prayer, and when he says "Amen", they are to put the muzzles of their shotguns up to his chest and pull the trigger, just so he can spare them this.
- This sounds very much like "Home Delivery", which he published in Nightmares & Dreamscapes. Apparently, he recycles.
- In 28 Days Later Selena tells Jim right near the start that if he got infected she'd kill him "in a heartbeat", and she proves this by killing one of her other friends when he turns. At the climax, she believes Jim has been infected due to the shockingly brutal killing the formerly gentle man commits. She can't bring herself to actually attack him.
- Earlier on Frank is infected but Jim can't bring himself to deliver the death blow, even though he knows he's only got seconds before they're all in danger and Selena is screaming at him to do it.
- In Army of the Dead, Scott Ward found himself having to kill his own wife when she was turned into a zombie during the Las Vegas outbreak. Scott's daughter Kate has to do the same as he turns into a zombie in the end.
- Blade has to stake his own mother in the first film; he believed she had died giving birth to him after a Vampire bite.
- He also gives Whistler a gun to shoot himself before he fully turns. Blade does an Unflinching Walk as a gunshot is heard behind him. Subverted when it turns out that Whistler missed and survived.
- In Blood Red Sky, after getting full confirmation that his Vampire Refugee mother Nadja has completely turned into a vampire and given in to her killer instincts, Elias (Nadja's 12-year-old son) sets off the explosives in the plane the vampires were holed up in, incinerating all of them in the humongous fireball that ensues.
- Subverted in the first Count Yorga film, one of the protagonist is given the chance to stake a female friend of his that been turned by the title character (she actually stands there and waits on him). He considers it but ultimately can't do it and leaves her in her undead state.
- Daylight's End: On the first day of the outbreak, Ethan had to put down his infected brother Evan.
- Parodied in Dracula: Dead and Loving It, where Van Helsing (played by Mel Brooks) invokes this trope as an excuse to not have to stake Lucy:
Van Helsing: It must be done by one who loved her in life!
Jonathan Harker: But I only liked her!
Van Helsing: Close enough!
- From Dusk Till Dawn. Seth has to kill his brother. Kate has to kill her father and brother after her brother found himself unable to kill the father and was infected as a result.
- I Am Legend featured the main character's dog being bitten by the "vampires" and he must put her down when it becomes obvious that the antidote he's been trying to develop didn't work. Worse than a lot of examples because the main character is the last human left in a city full of monsters, and the dog was his only companion.
- John Carpenter's Vampires. When John Crowe discovers that his Vatican liaison is withholding information from him, he threatens the priest, who refuses to believe that Crowe will harm a human being. Crowe responds thus:
"Listen to me, you fuck! My father kept a secret once. He had been bitten by a vampire. He kept it a secret from me and my mother. By the fifth day, he was turning. That night he attacked my mother. And then he came after me. I killed my own father, Padre. I got no trouble killing you."
- Living Dead Series:
- In Night of the Living Dead (1990), Barbara is forced to shoot her friend Ben after he dies and turns into a zombie.
- Depicted on a city-wide scale in the opening of Dawn of the Dead (1978), with disastrous results. Efforts by the Philadelphia Police Department to enforce Removing the Head or Destroying the Brain on all Zombie Infectees go over very poorly in the city's Black and Puerto Rican neighborhoods, leading to riots and the final breakdown of public order in communities that already didn't trust the police (and given what we see of them, it's not hard to figure out why) and saw their response to the Zombie Apocalypse as just an excuse to kill them and their loved ones.
- The remake of Dawn, meanwhile, had Andre snap after Norma kills his zombified, pregnant wife Luda, leading to a shootout in which the two of them kill each other. When the other survivors show up, they find Andre cradling his newborn daughter, who was infected in the womb and born a zombie.
- Resident Evil (2002). Matthew Addison has to kill his ally Rain Ocampo after she turns into a zombie.
- Non-fantastic example in The Searchers: Debbie Edwards's own family expect her uncle to kill her after they learn she's been indoctrinated by the Comanches who kidnapped her into becoming their squaw - and they have hardly any regrets because, after all, Debbie is now the enemy. Of course, since said uncle is a fanatical Indian-hating psychopath, Debbie's blood tie to him never even enters the picture until he actually has the opportunity to do it, and he experiences an Adopt the Dog moment.
- In Shaun of the Dead, Shaun has to kill his zombified mother. Subverted in the case of his zombified best friend; Shaun locks him in a shed in his back yard and they play video games together.
- Star Trek: First Contact: Downplayed on the "loved one" part, but when the Borg invade the Enterprise, Captain Picard makes it clear what must be done to all drones, even former crewmembers. He then shoots one Red Shirt whose assimilation has just begun, and later on he guns down a drone who used to be Ensign Lynch.
Picard: (to his security teams) You may encounter Enterprise crewmembers who have already been assimilated. Don't hesitate to fire. Believe me, you'll be doing them a favor.
- When Secker and Paxton in Taste the Blood of Dracula find vampirized Lucy in a casket, Secker tries to stake her, only for Paxton to chase him away, so that the task of slaying his daughter would befall on him alone. He fails because he takes too much time to do the deed.
- The first film in the The Twins Effect duology have the vampire hunter, Reeve, being infected with vampirism, and failing to procure the antidote on time, begs his lover, Gypsy, to pull this trope on him if he becomes savage. It did happen, eventually.
- In Zombieland, Columbus and Tallahassee come across Wichita and her zombie-bitten sister, Little Rock. They hand her the gun to do the mercy kill, but things don't go quite as they plan because they're faking the zombie bite just so they can get a hold of Columbus and Tallahassee's guns and truck.
- In one Anita Blake book, the parents of a dead girl ask Anita to do this for them before their daughter rises as a vampire.
- In Baltimore, or the Steadfast Tin Soldier and the Vampire, Baltimore has to do this not only to his wife, but his father, mother, and sister as well.
- In Blood Promise, Rose has to do this to Dimitri.
- Buffy having to stake the vamped Giles in the Buffy the Vampire Slayer novel The Lost Slayer.
- In the Discworld novels, Angua has specifically requested that Carrot do this if she ever ends up becoming as monstrous as her brother Wolfgang.
- Best known example from Bram Stoker's Dracula when Helsing shows the men first hand of Lucy's undead form after she "dies" and seeing she's more monster than human. Although he notes that he is willing to deal the final blow himself, he offers her fiancé Arthur the chance to do so instead, rationalizing that if Lucy were able to, she would have wanted Arthur to do it as well. All three suitors agree, and Arthur thanks Van Helsing for the chance.
- In the Perspective Flip book The Dracula Tape, Dracula uses this incident to advance his argument that Helsing is a sadistic psychopath.
- Invoked in-universe in Dream Park, when the casualties of the South Seas Treasure Game are sent back in make-up to "attack" their former comrades as part of a zombie horde. Gwen, acting under the Game Masters' orders, winds up in a duel with her out-of-game boyfriend Oliver, and he's so shocked that she has to whisper "Kill me, Ollie, please" before he'll play out the scene properly and strike her down with his virtual weapon.
- In The Dresden Files, Changes, Harry is forced to kill his vampire girlfriend Susan when she turns fully. The situation was further complicated in that the Red Court vampires that sired Susan were about to kill their daughter to activate a spell that would kill her family line, and by killing Susan, Harry could use the spell against the villains, destroying all members of the Red Court.
- Made even worse when one realizes that our hero knowingly manipulated the situation so that Susan would lose control and kill, thereby turning into the youngest Red Court vampire. He hates himself for doing it and will never forgive himself, even though it saved their daughter.
- Note finally that Susan had regained control in the final moments, and knew exactly what he was doing and why. The fact that she realized it was the only way to save their child, and didn't struggle, arguably made it even harder for Harry to cope with this trope.
- Dust Devils: Cody ends up having to destroy his friend and newly turned vampire Willet on Willet's urging to put him out of his misery. Cody later ends up destroying the body of his beloved father Jack to prevent him possibly rising up again as a vampire.
- Eden Green follows a rationalist attempting to cure her best friend of an alien needle parasite. As she begins to realize the seriousness of the situation, she resolves to do whatever is necessary to make sure the parasite doesn't spread.
- The Gardella Vampire Chronicles:
- Subversion in All Just Glass. The main character herself is a vampire hunter and witch who is turned into a vampire. Her sister, another hunter, wants to do this, but ultimately can't bring herself to do it.
- There's another subversion in the book that comes right before it in the series, Shattered Mirror. Sarah goes out to kill Kristopher, and then gets turned into a vampire.
- In I Am Legend, Neville must kill his reanimated wife when she returns.
- In the Magic: The Gathering novel Nemesis, Eladamri kills the Phyrexian Belbe, who was created from the corpse of Eladamri's daughter. Overlaps with Van Helsing Hate Crime in that Belbe had already gone through a Heel–Face Turn and was actively sabotaging the Phyrexians' plans. Nice Job Breaking It, Hero.
- In the Mercy Thompson novels, doing this to werewolves who can't control their "wolf side" is usually the duty of their closest werewolf relatives, but if they can't do it, the Marrok (Alpha-in-chief of all North America's werewolf packs) or his son Charles has to step in. The novels make it clear that both the Marrok and Charles have already done it too many times for their own peace of mind.
- In the post-Zombie Apocalypse Newsflesh world, it's accepted that if someone is about to amplify (become a zombie), even close relatives are expected to put the victim down for good, both as an act of compassion and to keep the victim from spreading the problem by attacking those around him/her. In the first book, we hear about a mother forced to kill her child and see an about-to-be-zombie shot by a close friend. Then there's Shaun performing a Mercy Kill on his lover/adoptive sister Georgia, which sends him into Sanity Slippage for the next two books.
- Old Yeller: After his loyal and brave dog contracts rabies, Travis insists to his mother that since it’s his dog, he must be the one to shoot Old Yeller.
- The Saga of Erik the Red: During the winter Thorstein Eriksson and Gudrid spend in the Western Settlement with farmer Thorstein and his wife Sigrid, people start dying from a mysterious disease (later revealed to be the doing of the draugr Gardi). Sigrid dies, but hours later comes alive again as an undead and tries to get into the bed of the sick Thorstein Eriksson. Her husband puts her to rest again by driving an axe into her breast.
- Happens to several characters in 'Salem's Lot.
- Another Stephen King instance in "Home Delivery", when a pregnant widow faces her reanimated husband in a Zombie Apocalypse. She's normally rather passive and indecisive anyway, even in normal situations, but discovers her Mama Bear side.
- A Song of Ice and Fire: One of Tormund Giantsbane's sons dies of exposure and comes back as a wight.
Tormund: Had to see to him m'self. That was hard, Jon. He wasn't much of a man, truth be told, but he'd been me little boy once, and I loved him.
- In "Lullaby", Vampire Hunter Holtz returns to his home to find Angelus and Darla have been there first to kill his wife and turn his daughter, whom he kills by throwing her into the sunlight. The act fuels his Roaring Rampage of Revenge against Angel in the present day.
- In "War Zone", Gunn had to stake his sister after she was turned.
- When Illyria takes over the body of Winifred Burkle, the most beloved member of Team Angel, none of them show any hesitation over trying to kill her. They were just totally incapable of achieving it.
Illyria: You held affection for this shell, and yet you strike at its form without remorse.
- A Running Gag is that whenever a member of Team Angel warns a co-worker to be ready to kill them if they turn evil, they agree a lot more readily than the other one finds comfortable. Especially Connor.
- On two occasions a cast member had to dismember the body of a loved one in the mistaken belief they had been killed by vampires.
- Subverted in "Double or Nothing". Angel is playing an Absurdly High-Stakes Game that if he loses will cost him his soul (which will turn him evil). He hands Cordy a wooden stake and says she knows what to do if that happens. When Angel does lose the game, Cordy instead rams the stake through the Big Bad's palm, holding him in place so Angel can lop off his head.
- Being Human (UK):
- Sort of done when Lauren begged Mitchell to stake her and he did. Only counts as a "sort of" example as Mitchell was the one who turned her into a vampire in the first place.
- Done totally straight by George to Mitchell. He even makes sure to tell him "I'm doing this because i love you."
- Now in the US version, Aidan is forced to stake Bernie, his ten-year-old neighbor, because as a child he cannot control his emotions or appetites. A little later on, Aidan again stakes Rebecca at her request.
- Blade: The Series:
- Krista does this to her mother after her plan to turn her into a vampire goes awry.
- Subverted in the case of Krista's uncle after he is bitten by Krista's newly-turned mother. Blade beheads him as a precautionary measure.
- Javier did this to his girlfriend on Blood Ties (2007).
- Buffy the Vampire Slayer, many times.
- Season Two is a protracted inner struggle for Buffy, who can't bring herself to stake Angelus in their first encounter. She ends up having to send him to Hell to stop Acathla when he'd just had his soul restored.
- In "The Harvest", Xander staking one of his best friends by accident. He couldn't do it and only survived because a panicked bystander unknowingly shoved the vamp onto his raised stake.
- In "Lies My Parents Told Me", Spike had to stake his newly-sired mother after it was made clear that she was a completely different person. And evil. And trying to shag him.
- Curfew features feral creatures called "mooks" which are created when humans are infected with a virus. In episode five, Ruby Newman defends the Donahue family from a group of mooks, but gets bitten and infected by one that wasn't dead yet. When she's unable to kill herself, her sister Kaye performs the Mercy Kill instead.
- Forever Knight:
- In "A More Permanent Hell" LaCroix is brought across by his early-teen daughter Divia to escape the destruction of Pompei, but when she declares that mortal rules should no longer constrain them, and they should become lovers, LaCroix is horrified, and beheads Divia and imprisons her remains in a sarcophagus.
- Later, in the final episode, Nick asks LaCroix to stake him so that he and Natalie can die together, telling LaCroix that he should do it because of their friendship. (The scene cuts away before the actual staking, though, so it's a popular fan theory that LaCroix instead smacked Nick in the head with the wood and brought Natalie across.)
- iZombie: In the season 2 finale, Liv finds out that Vaughn Du Clarke's people have experimented on some of the zombies kidnapped by Major, attempting to cure the condition. Unfortunately, the "cures" end up turning them into "full Romero" zombies. Drake ends up volunteering for an experiment to spare another zombie and goes mindless. Clarke then sics him on Clive, forcing Liv to shoot Drake in the head.
- A vampire hunter in a Sliders episode does this after finding his wife in a coffin before the other vampires swarm him. Quinn is ready to do this to Wade, except she hasn't been bitten and was just sleeping in the coffin.
- The second season episode "Heart" forces Sam to do this for Girl of the Week Madison, who has become a werewolf.
- Gordon beheaded his sister after she became a vampire, a fact which disturbs Sam and Dean. Part of this was probably because he tracked her down and killed her (in an episode showing that Friendly Neighborhood Vampires, or at least non-murderous ones, existed too) instead of her attacking him.
- Invoked by Meg when she possessed Sam and tried to convince Dean that his Psychic Powers had turned him evil, knowing that killing his brother would cause him the most pain and that what he tried wouldn't kill her, just Sam's body.
- When he's suspected to have the Croatoan Virus, Dean refuses to kill him or let anyone else do it, instead deciding to stay with Sam until he "dies".
- Bobby had to do this to his wife twice: when became possessed, he stabbed her, not knowing what else to do, and later kills her again when she comes back to life as a zombie.
Bobby: She was the love of my life. How many times do I have to kill her?
- The failure to do this quickly enough, when his infected friend hands him a silver-loaded pistol and begs him to end his suffering, is what set Eric Cord on his quest in Werewolf (1987).
- Many times in The Walking Dead (2010), given the fact that it's a show about the zombie apocalypse. A few notable examples:
- Andrea held her sister Amy's body until she rose again as a walker before shooting her in the head. (Shooting or stabbing walkers in the head is the only way to stop brain activity and kill them.) In season 2, Hershel is unable to kill his zombified family members and instead keeps them in a barn. Shane goes and kills them all anyway.
- After the season 2 reveal that the virus is in all of them and when they die, regardless of if they were bitten or not, they will rise again as a walker, it becomes standard procedure to stab or shoot their loved ones in the head whenever they die. One of the more disturbing examples is Carl, a young teenage boy, shooting his mother in the head after she dies in childbirth.
- In the Sound Horizon song "Koibito wo Uchiotoshita Hi" ("The Day I Shot Down My Lover"), a girl must kill her lover - who saved her life from a monster - when the venom from his battle wound causes him to turn into a monster himself.
- Dungeons & Dragons: In the Ravenloft setting, Dr. Rudolph Van Richten dedicated his life to hunting vampires after his son fell victim to one. The first vampire he killed was his own son, who asked him to do it before the transformation could corrupt his soul.
- In Baldur's Gate II, your love interest (if you have one) gets turned into a vampire and you have to kill them. They'll be only partially turned, so it works like normal dying, not vampire "dying", except that resurrection spells won't work. There's another way to bring them back to life, though.
- In Crisis Core: Final Fantasy VII, Zack has to kill his mentor, Angeal, who actually makes himself monstrous to make it easier for Zack to kill him.
- The backstory of Daemon Summoner sees your wife, Emily, being converted into a vampire, and you'll need to eliminate her so she may rest permanently in peace. You face her as early as the first stage, but she will escape no matter what; you then fight her again in the asylum level where you finally kill her for good.
- In Dark Souls III, if you complete Siegward of Catarina's questline before facing Yhorm the Giant, Siegward will join you for this boss battle, revealing that the "duty" he spoke of earlier is a promise he made to Yhorm, his old friend, long ago—namely, to Mercy Kill him, should he ever be brought back to (un)life after sacrificing himself to the First Flame. To this end, Yhorm had, in fact, given Siegward one of two Swords of Giant-Slaying (the other is kept in his boss arena), which make the boss fight a lot more manageable. If you manage to get the other one and equip it yourself during the battle, you and Siegward can steamroll the game's biggest Damage-Sponge Boss in just a few hits.
- In Final Fantasy Adventure, the hero is forced to kill Amanda, a fellow gladiator, after she gets bitten by Medusa.
- In Final Fantasy Tactics, when Ramza has foiled the Lucavi's plots once too many times, Folmarv abducts his older half-brother, Zalbaag, and turns him into an undead monster. Although Zalbaag is perfectly conscious and aware of his condition, his body will relentlessly pursue Ramza and try to kill him, at which point he begs the younger Beoulve to put him out of his misery. Granted, Zalbaag was a bit of a jerkass throughout the game, but he was on the path of redemption and actually cared for his family, making this a Tear Jerker.
- Played with in Golden Sun: Dark Dawn when Sveta realizes that activating the Apollo Lens required to end the Grave Eclipse will kill her brother, who was transformed into a monster of darkness by the games main antagonists. Made worse by the fact that she is the only one who can do it.
- Subverted when he regains his memory and knocks her away from it so he can fire it himself, ending the Eclipse.
- In The Last of Us, Henry ends up killing his younger brother Sam after he gets infected. He takes his own life immediately after.
- Left 4 Dead provides the page image: In Zoey's backstory, her father was bitten by the Infected and asked her to shoot him before he turned. A few weeks later, she found out that she was immune to the infection... which means that he probably was too.
- Majyuo: If you complete the game as a human (as in, you failed to obtain the final transformation item), it is all but shown through the screen smashing to black with the sound of a gunshot that the protagonist blew his own daughter's brains out to spare her from her fate as a demon.
- In Melty Blood, Riesbyfe's path takes place in a timeline where Sion fell to vampirism, and she had to kill her. Then she had to do the same thing to Dust of Osiris; a copy of a version of Sion from a possible future that never came to be (It's complicated). She does this knowing that Dust of Osiris is sustaining Riesbyfe's existence. "I hope to see you again, my friend; after the darkness."
- Ending C in NieR has the protagonist killing his Love Interest Kainé after the Shade part of her takes over.
- At the end of ObsCure II, after Kenny undergoes a Face–Monster Turn, his sister Shannon is one of the two characters who faces him in the Final Boss fight. Afterwards, Amy, who Kenny had raped and impregnated, undergoes an Express Delivery of his monster spawn, and the Bolivian Army Ending that follows has Shannon and her boyfriend Stan getting ready to face her "nephew".
- Subverted in Octopath Traveler II. Harvey uses the blood of Osvald's wife to make a golem which he sics on Osvald, forcing him to put it down. Osvald initially thinks it actually is Rita and has an appropriately horrified reaction to the "reveal." However, he then realizes that while Harvey used Rita's blood in the experiment, he didn't give her soul to the golem, simply making it a creature with some of her traits rather than literally being her.
- Pretty heart wrenching in Parasite Eve when the police dog, Sheeva, goes berserk from Eve's influence. Ben, who is only 8 years old and is the son of Daniel, Aya's partner, chases after the dog and almost gets caught by monsters along the way. Once Ben catches up to Sheeva in a big empty room, he clings to the dog, wondering what is wrong with his new friend. Police chief Baker arrives and takes Ben away from Sheeva, telling Ben that Eve turned the dog into a monster. Within that moment, Sheeva mutates into a 3-headed beast, wounding Baker off-screen. Once Aya arrives, Ben tells Aya that Sheeva is already dead. Cue Boss Battle. The next day, Catherine informs you that Baker worked with Sheeva when he was a rookie (that's an old dog...) and that it must have been painful for him to shoot at her.
- Even worse when Aya meets the original Eve, who had been using the one that had caused the events of the game as a puppet controlled via a donated organ containing the mitochondria that took over and mutated the host. This monster resides in Aya's sister, Maya, who hasn't aged a day since they were separated. To twist the knife, the parasite lets Maya "chat" with her sister for a moment. The little girl clearly has no idea where she is or what she's been used for, not even recognizing her sister since her last memory had Aya just as young as she is, and almost immediately screaming about "the heat coming back". The somber track that plays during the twisted reunion is then overlapped with the typical boss theme of Mitochondria Eve after the parasite mutates Maya's body while reminding Aya that this is still her sister after the woman justifiably rages at being taunted with her sister being so close yet out of reach. It doesn't stop through the whole extremely difficult fight, as a reminder to the player what must be done.
- Done in self-defense in Phantasmagoria. Heroine Adrienne is being padlocked into a torture chair which is rigged to kill her when a lever is pulled by her demon-possessed husband Don. At first, she tries to reach out to him with a snowman ornament and pleading that she loves him, but this will fail and he will pull the lever anyway if no action is taken. She has to pull the lever and make the rigging kill Don to save herself.
- In Prince of Persia: The Sands Of Time, the Prince finds himself having to fight his father as a Sand Demon.
- Resident Evil:
- In Resident Evil – Code: Veronica, Steve is forced to kill his now-zombified father, causing him to have a brief Heroic BSoD.
- In Resident Evil 6, at the beginning of his campaign, Leon Kennedy futilely attempts to talk the zombified President Adam Benford (who is also Leon's close friend) down, but ultimately he is forced to shoot him.
- Choose the bad ending in Resident Evil 7: Biohazard (save Zoe, not Mia, which results in you having to fight Mia) and this is what Ethan is forced to do.
- In Starcraft: Brood Wars Zeratul is forced to slay his Matriach Razhagal after it turns out she was enslaved by Kerrigan.
- In Tales of Symphonia both Kratos and Regal were forced to Mercy Kill their lovers when they were mutated by Exspheres.
- The most heart wrenching decision you'll have to make in The Walking Dead (Telltale) comes at the end where Lee is about to succumb to the infection that will turn him into a zombie, and the player must decide whether to have Clementine shoot him or simply run and leave him. It seems like a pretty clear-cut choice, and it would be for most, but given the hell that poor Clementine has been through for most of the game, having to shoot the man who's faithfully protected her through it all must seem like murder. Whether she does it or not is up to the player, but either way, its hard to watch. This situation comes up more than once a season, with the drama therein played to the hilt every time.
- Jack is forced to do this in Wild ARMs to Elmina, who he was very close to when they were Fenril Knights in Arctica. She's been turned into the demon Lady Harken and the only way to free her is a battle to the death.
- Saber in Heavens Feel route of Fate/stay night, though in this route she's not a love interest so much as a very close friend. Quite a downer when the Taiga Dojo for not doing points out if you want to save her you can go play another route, because it's not happening here (assuming the resultant horrifically Bad End didn't floor you already).
- Doing this to Sakura instead of trying to find a way to save her, on the other hand, is not recommended, as this will net you a Bad End where Shirou effectively becomes Kiritsugu 2.0, with no qualms about killing anyone in the way of winning the Holy Grail War, up to and including Rin and Ilya.
- Akiha makes you promise this in Tsukihime when her demon blood is taking over. Averted in the True End, though, when you Take a Third Option by returning your life force to her. The Normal End is actually worse than if you had killed her. Also barely averted in Kohaku's route with Akiha again. Not Satsuki though. She was just a classmate, so Shiki is just upset he had to kill someone at all.
- The Adventures of Dr. McNinja has an arc where Mitzi is rather quick to do this to Dark Smoke Puncher when he gets possessed by a ghost. She's got good reason, though; for all she knows, the thing has outright killed her son and is using the body as a puppet, and she's being practical. Gordito, however, manages to drive the ghost out before that's necessary.
- In Charby the Vampirate when Victoria comes back as a vampire with an altered personality and tries to turn Victor he puts her back in the ground for good.
- The Left 4 Dead comic shows Zoey's back story that occurred a week after the zombie outbreak. A zombie breaks into the apartment and bites Zoey's mother. She gets infected and attacks Zoey's father, which forces him to shoot her dead. Fearing that he is now infected, Zoey's father asks her to shoot him, which she tearfully does so. This scene is more gut-wrenching when Zoey discovers that the carrier gene (what prevents people from becoming a zombie) is passed down on the father's side on the family, thus there was a chance Zoey's father could have been just fine.
- This is zigzagged in The Order of the Stick when Durkon is turned into a vampire. The reader is left with time to think about what this means will happen, and the other main characters are shown thinking about it too and being really sad about it. They don't mention having to kill him, but it really doesn't need saying. Then, of course, since that's the obvious way for the plot to go, it doesn't: Durkon's vampire master is killed, he becomes free-willed again, and he turns into a Friendly Neighborhood Vampire who rejoins the group and finds a way to control his need for blood. Except he really isn't friendly, or even "Durkon" anymore— he's a vampiric spirit inhabiting Durkon's body, holding his actual spirit helpless while he works to bring about the literal end of the world. This all leads to a confrontation between the party and Vampire!Durkon, during which Real!Durkon's spirit overwhelms the vampiric puppeteer long enough to lower his defenses, finally allowing this trope to be played straight (except that it might be a bit of a stretch to call Belkar a "loved one").
- In the Penny Arcade three part story, the Cardboard-Tube Samurai is forced to kill an old ally who has been possessed by a cursed sword.
- Sluggy Freelance:
- In "Vampires", Torg has to stake Valerie, whom he at least thought he was in love with — with the twist that she'd secretly been a vampire all along.
- Parodied in "28 Geeks Later", a zombie parody with zombies replaced with animalistic hypergeeks whose brains have been altered so that their empathy and social skills have been replaced entirely with theoretical smarts, making them geniuses but ravaging maniacs at the same time. One character is infected with just one of the earwigs spreading the condition, making him just a bit geekier, but his crying daughter beats him to the ground with a club anyway (though he doesn't die). Zoë asks why she did it and she explains it's because he's a geek now and she's a cheerleader.
- Vamp You has included a few instances of people trying this trope, but it generally never works out. Usually, there just ends up being two vampires.