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->''"You put fire to everything you touch, [=McNulty=], and then you walk away while it burns!"''
-->-- '''Lester Freamon''', ''Series/TheWire''

A character defined both by their obsessive loyalty towards a target character and by their vastly divergent (and [[SlidingScaleOfIdealismVersusCynicism comparatively "cynical"]]) moral code.

The Poisonous Friend is usually attached to an IdealHero or an AntiVillain. They tend to consider their "master" a person to be worshipped or protected at all costs -- even ones that the master [[WhatTheHellHero would not knowingly permit]].

For example, if the master is a [[TheFettered Fettered]] ActualPacifist or a NobleDemon who is [[ThouShaltNotKill completely against killing his enemies]], the Poisonous Friend might pay lip-service to this trait while the master is nearby... and then turn around and butcher the enemy behind the master's back. If caught, they'll claim they just [[IDidWhatIHadToDo "did what had to be done"]]. [[HorribleJudgeOfCharacter Few masters catch on.]]

Sometimes the master's influence gets through to the Poisonous Friend, with varying results. In other cases, the PoisonousFriend continues to pose a danger both to the master's other friends [[TheFarmerAndTheViper (through jealousy)]] and to the enemy. The LoveInterest is in [[FriendVersusLover particular danger]] of the Poisonous Friend if [[TheyWereHoldingYouBack they suspect them of making the master "vulnerable"]].

Though sometimes introduced as anti-heroes or turncoats from the other side, they cease to be those things because they place their fundamental loyalty upon the shoulders of their "master". Basically they become a good guy's secretly-evil minion, or a bad guy's [[EvilerThanThou much-badder]] [[TheDragon sidekick]].

This character is often used when writers don't want to stain the "innocent" master's hands, but still need a way to deal with those pesky defeated enemies. Even friends who have been explicitly told to behave or otherwise decided to hold back can still function in this regard if they have done something [[KickTheDog bad]] [[MoralEventHorizon or really bad]] enough to intimidate the villains. If a particularly [[TheFettered noble]] and idealistic hero [[SmallStepsHero cannot wrong anyone]], but has a particularly [[SociopathicHero cruel]] and [[BloodKnight ruthless]] poisonous friend, the villain may hesitate to take advantage of that hero's idealism and kill him out of fear of what [[RoaringRampageOfRevenge his]] [[TheUnfettered buddy's]] [[KillEmAll response]] [[UnstoppableRage could]] [[ThereIsNoKillLikeOverkill be]].

The name of this trope comes from a song by the band Music/{{Seabound}}.

If their behavior actually starts to rub off on the hero, it's ToxicFriendInfluence. If the hero retains their own morals, but still knowingly tolerates what this character gets up to, see PsychoSidekick. If the character is the hero's second-in-command, then his loyalty to the hero likely makes him TheCreon.

Contrast: PsychoSupporter, TheOnlyOneAllowedToDefeatYou, LoonyFan, TokenEvilTeammate, ShootTheDog. Compare BigBadFriend. Not to be confused with PoisonousPerson, in which someone is ''literally'' poisonous, though they can be combined. Also not to be confused with FalseFriend, in which one deceives another as being their friend, only to have an ulterior motive to do so. A MysteriousBacker might turn out to be one of these.


[[folder:Anime and Manga]]
* Subverted in ''LightNovel/TheTwelveKingdoms:'' In the last arc, Kouya initially appears to be a PoisonousFriend to his leader, Atsuyu; he murders dissidents regularly and claims to have "exiled" them when Atsuyu, who is presented in a positively saintly light, asks. However, Atsuyu is revealed to be a ManipulativeBastard who abuses Kouya's extreme loyalty to get away with atrocities while keeping his own hands clean.
* ''Manga/DeathNote:'' Misa is unwaveringly faithful and supportive of Light Yagami -- and also much cruder and more indiscriminate in her use of the Death Note, which Light considers an insult to his goal of punishing only criminals.
** Mikami's even worse, killing exactly a page a day, but killing reformed criminals and those that Light thought were redeemable or innocent.
* ''Anime/CodeGeass'' has a pseudo-sibling version of the trope in Rolo, who has an obsessive devotion to his "brother" Lelouch... so much that he wants to prevent Lelouch from reuniting with his real sibling, and [[spoiler:murders Lelouch's possible love interest when Rolo decides she might get in the way of this goal.]]
** Alicia Lohmeyer is this to Nunnally, as she tries to go behind her back on multiple occasions and take a much more hardline approach, as she cares nothing for the Japanese.
** Diethard is another extremist among Lelouch's company. When Suzaku is made Euphemia's Knight, Diethard calls for him to be assassinated. Lelouch suspects that he talked Kallen into trying to kill Suzaku at a party for him at the Ashford Academy, and warns him not to interfere with the military.
** V. V. is a Poisonous Brother to Charles. He is so devoted to their goal of "a world without lies", [[spoiler:he murders Charles' most beloved consort, Marianne (which has the side effect of setting the events of the series in motion), among other things done behind his brother's back]]. None of this is lost on Charles, who, fed up with V. V.'s lies after a series of failures, [[spoiler:[[KickTheSonOfABitch takes his code and leaves him to die]]]].
* Fiore from the ''Manga/SailorMoon R'' movie is a textbook example; obsessed with his friendship with Mamoru to the point that he'll destroy Earth for his sake, even though that's not at all what Mamoru wants.
* Yubel from ''Anime/YuGiOhGX'', one of Judai's Duel Monsters, who he apparently sent into outer space when she started killing anyone who defeated or upset him. She now holds a homicidal grudge against Johan because of his friendship with Judai. [[spoiler:she gets better after she and Juudai fuse their souls]]
* TheChessmaster Kyoya Ohtori (and, to a degree, all other male members of the ''Manga/OuranHighSchoolHostClub'') is utterly devoted to the idealistic and naive club founder Tamaki Suou, and is not above using dirty tricks and threats to cover up for his blunders from the shadows, which Tamaki generally fails to notice. This is most evident in episode 14 ("Covering the Famous Host Club").
* An especially absurd example would be [[TheDragon Legato]] from ''Manga/{{Trigun}}'', who decides to torture and kill Vash while Knives, the BigBad, is recovering from his last encounter with Vash, knowing that Knives will kill him when he wakes up.
** [[spoiler:In the manga, he does. In the anime, Vash does it first [[BatmanGambit because Legato knows that killing someone will cause Vash greater anguish than anything he could do.]] [[EvilPlan His goal and Knives was]] "eternal suffering to Vash the Stampede." Legato accomplished this by forcing Vash into a SadisticChoice, where he either had to kill Legato himself, or be indirectly responsible for Legato killing Vash's friends.]]
** Also Wolfwood, most notably when he shoots Zazie the Beast, who looked like he might have been calming down. [[spoiler:Vash's idealism has infected him so badly by this point that he ends up feeling horribly guilty over everyone elses' reactions and does a HeelFaceMole, which gets him killed.]]
* Yuno from ''Manga/FutureDiary'' is Yukiteru's creepy stalker-for-a-girlfriend. She'll gladly risk her own life to protect Yuki, and she won't think twice about slaughtering anyone who dares to harm him. She's also extremely jealous, and Yuki finds himself struggling to convince her not to kill his friends.
* Johan of ''Manga/{{Monster}}'' served as Anna Liebert's Poisonous Brother, murdering anyone their pursuers might have possibly used to pinpoint their location, before she finally caught on and [[spoiler:shot him in the head. He got better.]] Johan also helps Tenma's promotional woes. By killing off all his superiors that were keeping him down.
* Alucard of the ''Manga/{{Hellsing}}'' Organization clearly qualifies as Sir Integra's anti-conscience by the way he is able to stir Sir Integra into giving him the most ruthless orders so he can indulge his bloodlust as well as succeed in whatever mission he is sent to.
* Shizuru of ''Anime/MaiHime'' could be seen as being one of these to Natsuki; the latter seems pretty horrified when she sees that Shizuru has [[spoiler:destroyed First District Headquarters, and her defeating Yukino and Nao and by proxy killing their loved ones- Haruka, and Nao's mother]] in the name of 'protecting her'.
* Maki from ''Manga/MyBrideIsAMermaid''.
* Paul von Oberstein plays this to Reinhard in ''Anime/LegendOfGalacticHeroes'', [[spoiler:purposefully delaying the information that a faction opposing Reinhard was carpet bombing a planet with nukes]] and later [[spoiler:intentionally or unintentionally causing the death of Reinhard's moral compass Kircheis]].
** Walter von Schenkopp occasionally plays this role for Yang Wenli, often suggesting that Yang should consider seizing power for himself, forming his own nation, or [[spoiler:killing Reinhard after being ordered to surrender just has he has the latter dead in his sights]]. This is mostly because Schenkopp honestly feels Yang would do better than the pack of {{Ungrateful Bastard}}s they've been working for who have alternately [[spoiler:ignored intelligence or advice from people smarter than them, and (consequently found themselves staring down the barrels of Imperial particle-beam cannons) or screwed Yang over and/or the Alliance over even after Yang just got through saving their asses]]. One of the prime differences between Reinhard and Yang is that Reinhard listens to Oberstein, while Yang usually rejects Schenkopp's suggestions due to [[HonorBeforeReason his moral code]] and [[BrilliantButLazy general lack of ambition]].
*** Another is the fact that Oberstein is a brilliant strategist where Schenkopp is a bruiser. The former's advice is somewhat better thought out and presented.
* ''Manga/BlackCat'': In the anime, Creed Diskenth takes this to creepy extremes. He has such a constant hard-on for Train that at one point he ruthlessly butchers three intelligence officers for referring to Train as 'that guy'. The kicker is that he does this just after Train, once a heartless assassin, reforms and abandons the life of a killer, deciding to never take another life. Train pays little attention to the fact that Creed goes on a killing spree anytime Train's honour is insulted.
* ''Manga/PandoraHearts'':
** Gilbert is utterly dedicated to his master Oz and will do anything to protect him. Although he hasn't yet killed anyone (onscreen, anyway) for Oz's safety and well-being, he's tried, without any hesitation - despite being the gentlest, sweetest, most pathetic character of the series. However, his backstory flashbacks show that he cold-bloodedly allowed himself to be adopted by an 'enemy house' to become nobility and to steal their secret family weapon (the Chain called Raven), and then became an assassin, all in order to gain the power to save Oz. [[spoiler:It gets very, very worrying when poor Gilbert starts experiencing a nearly overwhelming compulsion to kill Alice, despite the fact that Oz adores her.]]
** Oz himself has had a scary unnatural breakdown in which he wanted to do this for Alice, to stop her from suffering [[spoiler:by killing ''her'']].
** And let's not even get in to the absolute {{Yandere}} mess that is [[spoiler: Jack]]. Basically, it's safe to say that nearly everyone in the cast is a PoisonousFriend to someone else.
* ''Manga/HunterXHunter'': [[spoiler:Pouf]] has become this to [[spoiler:the BigBad Chimera Ant King Meryem]]. After [[spoiler:Netero's suicide attack nearly killed Meryem and left him an amnesiac, Meryem forgot his MoralityPet Komugi along with his near HeelFaceTurn. A HeelFaceTurn that Pouf disliked]]. [[spoiler:Pouf]] is determined to kill [[spoiler:Komugi to keep said HeelFaceTurn from happening again]].
** His HeelFaceTurn in no way involved making nice with the heroes. It probably didn't even involve not conquering the world. It just involved attempting to discuss terms with Netero like civilized beings. Which, all things considered, was a pretty huge breakthrough.
*** Especially since the last time it looked like he was having a [[ImAHumanitarian moral crisis]] (because of Komugi) he turned out to be leading up to triumphant laughter over how much more marvelously powerful it meant he was, that he could kill and eat any human despite our newly recognized [[HumansAreSpecial tremendous variety of potential]].
*** Too bad Netero was determined to stick with the blowing up plan. On the other hand, Meryem is the scariest thing ever, so I can understand the desire to try to wipe him out with no caveats.
** Killua Zoldyk knows all about sneaking behind friends' backs to get a morally questionable, if logically justifiable, job done. Unlike most of the rest of his family, however, he tends to keep the body count fairly low and the collateral damage to his relationships as minimal as he can.
* ''Anime/MagicalGirlLyricalNanohaAs'':
** The Wolkenritter go out to complete the Book of Darkness despite Hayate ordering them not to, [[DownplayedTrope but they do it regretfully and only because they believe it's the only way of saving her]] (which is not far from the truth). They go so far as to [[ThouShaltNotKill avoid killing people]] so that Hayate won't be responsible for murder.
** Reinforce, after seeing that [[spoiler:the Wolkenritter have been absorbed into the book]], targets those she thinks are responsible: [[spoiler:Nanoha and Fate]]. Hayate makes it very clear that this is ''not'' what she wants.
* ''LightNovel/KinosJourney'': Kino meets a woman traveling with the intent of spreading peace, but the man she is traveling with is a highly skilled gunman. He kills people trying to attack the woman and she is none the wiser.
* Conrad Weller in ''LightNovel/KyoKaraMaoh'' quite frankly states that he is this to Yuuri in relation to both Greta and Hube, who respectively tried to kill Yuuri to please her racist guardians and to [[DeathSeeker get Conrad to kill him]], and who Yuuri wants to save and protect when they're disabled afterward. Conrad's first priority will always be Yuuri's safety, no matter how cruel he has to act.
* In ''Manga/{{Naruto}}'' [[spoiler:[[WellIntentionedExtremist Danzo]]]] is revealed to be one to his {{Rival}}, [[spoiler:The Third Hokage, Hiruzen Sarutobi]]. In an effort to keep the village safe, and prevent the idealistic [[spoiler:Hiruzen]] from having to tarnish his image [[spoiler:Danzo created Root]], a Black Ops organisation that has been involved in all sorts of unpleasant business over the years, all, at least in his mind, for the good of the village.
* A lot of characters follow this pattern in ''LightNovel/{{Durarara}}'':
** [[spoiler:Izaya]] is revealed to be this to [[spoiler:Shinra]]. How bad is [[spoiler:Izaya]] willing to protect [[spoiler:Shinra]]? Well [[spoiler:it all started in middle school when a student named Nakura tried to stab Izaya after trying to bet on him and losing the money because Izaya purposely didn't succeed. Izaya didn't expect anyone to protect him because he was technically getting what he deserved which is why he panicked when Shinra jumps in the way of the knife. Izaya swears that Nakura will regret this for the rest of his life. After that, he stalks Nakura after that incident and continues to keep in touch with him in order to destroy his life when the time is right. He frames him for two major incidents at the end of the novel and outright tells him that those bosses will get him.]]
** Mikado, Kida, and Anri are all willing to be this for the naive, nice people they believe the others to be.
** Walker and Erika are this for Kadota, though he has some idea about what they're doing while he averts his eyes.
* ''Anime/PuellaMagiMadokaMagica'':
** Homura to Madoka. She threatens to kill [[spoiler:Mami]], attempts to kill [[spoiler:Sayaka, so that Madoka won't have to bear the pain of seeing her die or become a witch]], and in fact does kill [[spoiler:Kyubey, not that it sticks]]. Though, in her case [[spoiler:[[GroundhogDayLoop she tried everything else first]]]].
** ''Manga/PuellaMagiOrikoMagica'' demonstrates this beautifully where Madoka [[WhatTheHellHero calls Homura out for only protecting her]]. Homura responds by saying to never ask Homura to stop protecting Madoka.
** ''[[Anime/PuellaMagiMadokaMagicaTheMovieRebellion Rebellion]]'' takes this UpToEleven. [[spoiler: Homura literally ''hijacks'' Madoka's goddess powers and imprisons her in a LotusEaterMachine.]]
* In ''LightNovel/TheLegendOfTheLegendaryHeroes'', Miran Froaude is this to King Sion Astal.
* In the ''VisualNovel/AceAttorneyInvestigations'' manga, Marco Swindell, who is extorting money out of the head doctor of the Jiffy Clinic, is found dead of poisoning. The culprit turns out to be [[spoiler:a patient, Clive Fortuna]], who decided to kill him to free Dr. Jiffy of him. Dr. Jiffy tells the culprit that he finds [[spoiler:his]] devotion touching, but that [[spoiler:his]] crime must be punished.
* [[DarkMessiah Sensui]] of Manga/YuYuHakusho is an odd subversion: due to his BlackAndWhiteInsanity, he developed a new split personality each time he needed to do something he considered evil, leaving his central persona pure.
* In her DeathbedConfession, Baron Hisamichi in ''Manga/{{Ooku}}: The Inner Chambers'' admitted that she [[spoiler: poisoned Yoshimune's older sisters (and a rival claimant to the throne) to ensure that Yoshimune would become shogun. She was ''twelve'' when she poisoned Yoshimune's sisters.]]
* Christopher Shouldered serves as this to Firo in the ''LightNovel/{{Baccano}}'' LightNovels. Thanks to Firo's uncanny [[WeirdnessMagnet lunatic]] [[MagneticHero magnetism]], the flippant, AxeCrazy Christopher decided that they were friends almost immediately upon crossing paths with him. His first order of business is helping Firo find the (not actually) kidnapped Ennis, committing copious amounts of murder along the way. Firo gets a brief reprieve from Christopher when he winds up in Alcatraz and Chris goes to Chicago... only to find himself saddled with ''another'' self-appointed PoisonousFriend, [[spoiler:Ladd Russo]].
* In ''Anime/DragonBallSuper'', Jiren is this to Universe 11's Pride Troopers. [[spoiler:Pride Troopers all gravitated to him because of his power and they all consider him their friend, but Jiren absolutely refuses to do anything with them, seeing them as stepping stones to his goals.]]

[[folder:Comic Books]]
* ''ComicBook/JohnnyTheHomicidalManiac:'' NNY meets a fan who idolizes and copycats his work because he thinks it's ''just that cool''. NNY is outraged because he doesn't kill for the fun of it -- he does it because he needs the outlet to survive his role as a "Flusher" for the world's negativity. (NNY then proceeds to do to the copycat what he does to everyone.)
** Also, oddly enough, this becomes an example of EvenEvilHasStandards as well. It is implied by NNY's killing rant that the impostor raped a woman, and that NNY would "never do...that". (Though, this may be more because NNY loathes physical contact than anything else.)
* Depending on who is writing, Franchise/{{Batman}} is this to the Justice League, and the superhero community at large. Hard not to be when your team mates stumble across detailed plans on how to kill each and every one of them in case they go rogue and have to be put down.
** He's this especially to Franchise/{{Superman}}.
** Although Batman did at one point say that he trusted the Justice League to be the ones to take him down, should he ever [[FaceHeelTurn go rogue]].
** [[ComicBook/XMen Professor Xavier]] had similar plans at one point. Given the number of times a hero's gotten {{Brainwashed}} or hypnotised or had some other EnemyExchangeProgram weirdness happen to them, [[ProperlyParanoid that probably isn't such a bad idea.]] The fact that he included one for taking ''himself'' down probably mitigated any hard feelings.
** In one JMichaelStraczyniski-penned ''SpiderMan'' issue, Spidey defeats the villain-of-the-month using a modified version of a plan he had to take down the Hulk, and mentions that most of the Marvel Universe's heroes have plans for taking each other down, although it isn't something they like to talk about.
* DC Comics' controversial ''ComicBook/IdentityCrisis'' storyline turned a small group of lesser Justice League members into this for the League at large. While the Big Three heroes like Superman, Batman, and Wonder Woman went about living and acting on their ideals, lesser members would do necessary "clean-up" jobs to preserve the League's secrets, primarily by having Zatanna wipe minds and reprogram someone's personality. Used as a {{Retcon}} to explain away events where the villains learned (or should have learned) the identities of various heroes, but never acted on them.
** Especially applied to the odd devolution of Doctor Light from a physics genius able to make light waves sit up, roll over and otherwise do basically impossible things (i.e. turning afterimages into explosive holograms) who could convincingly take on the whole Justice League into a ButtMonkey with a ray gun that was basically a suped-up flashlight, who regularly lost to the Teen Titans. What happened to him caused many villains to look at the heroes as having crossed a MoralEventHorizon.
* DC Hero team, [[ComicBook/BatmanAndTheOutsiders The Outsiders]]. The Outsiders have had three different incarnations over the years. They were founded by Batman, whose ties to the League had become strained. He has stated his intent to use the team as a black ops version of the Justice League, able to take the proverbial "fall" in public opinion where the League cannot.
* One of the interpretations of ComicBook/CaptainAmerica's sidekick ComicBook/{{Bucky|Barnes}} was as the guy who did the backstabbing Cap was too moral to do.
** Another is that Cap wasn't too moral for that kind of work, but that his public image could not be so sullied. There are several instances where Cap is portrayed as accepting, even approving, of Bucky's "extracurricular activities," although there are quite a few where he is not.
** Averted in the [[ComicBook/UltimateMarvel Ultimate universe]], where Cap fights the way a real soldier would.
* In ''[[{{Comicbook/Nexus}} Nexus]],'' Kreed was a super-strong alien called a Quatro who had lived all his life as a member of an assassin's guild. Killing was the only thing he knew how to do, but he had come to find it pointless. When he learned of Nexus, he came to revere him as a man who had learned how to use those skills in a worthwhile cause, and he followed Nexus unquestioningly like a loyal puppy, even at times when Nexus himself was showing terrible judgment, and Kreed would threaten terrible violence to anyone who he perceived as a threat to his hero. When Nexus finally decided he trusted Kreed enough to send him on a mission -- to hunt down and execute a list of murderers for the [[SufficientlyAdvancedAliens Merk,]] a task Nexus himself had always despised -- Kreed and his fellow Quatro Sinclair went mad with bloodlust, going on a wild killing spree that Nexus was only able to halt after countless innocent people had been already killed.
* ComicBook/{{Huntress}} was this to ComicBook/BlackCanary in pre-reboot ComicBook/BirdsOfPrey. She was extremely loyal to the Canary personally, but there was no question that she remained one of, if not the, darkest antiheroes in the DC universe. Interestingly, however, she did moderate her behavior so that Canary would be comfortable working with her; Canary did not really see Huntress' dark side until Huntress was about to throw Yasemin off a building and Canary had to talk her out of it. Canary made her final decision to leave the group directly after this incident, which seems not to have been a coincidence.

[[folder:Fan Fiction]]
* The reformed Terminator Arnold Davis in [[http://www.fanfiction.net/s/7153098/1/The_Chronicles_of_Utopia The Chronicles of Utopia]] becomes the protagonist's right hand man when the two begin their business venture and when the main character becomes embroiled in the politics of Oerth. While the main character Asher has a fairly idealistic and positive view of people in general, Davis is far more cynical and mistrusting of mankind and plays the devil's advocate to Asher on many occasions, asking the tough questions. When Asher forms his own empire in [[http://www.fanfiction.net/s/7893756/1/The_Chronicles_of_Utopia_Volume_II The Chronicles of Utopia Volume II]] he becomes the kingdom's spymaster and head of security.#
* In ''Fanfic/ChildOfTheStorm'', Loki and Natasha, and occasionally Clint, generally serve as this to the Avengers, (and in Loki's case, more specifically, to Thor), doing the dirtier jobs behind the scenes that the Avengers as a whole can't do publicly because of their public image.
** Doctor Strange serves as this to the heroes, and particularly Harry, being willing to use extraordinarily ruthless and downright amoral means to remove threats and potential threats to them and to the timeline as a whole. This does not make him the most popular person around, though even the heroes who like him the least grudgingly admit that he's useful. Villains, by contrast, are scared witless of him, and with good reason.
* Takashi in [[Fanfic/DevaSeries the Deva Series]] is one to [[Franchise/LyricalNanoha Hayate]], using underhanded means to protect her interests, including [[spoiler:killing the leaders of the Circles after finding out about their plan to nuke her school]].
* Connie Poirier is this to [[ComicStrip/ForBetterOrForWorse Elly Patterson]] in ''FanFic/TheNewRetcons'', enabling her to blame everyone but herself for her misfortunes, lie about [[spoiler:having a baby out of wedlock and putting it up for adoption, and not telling Michael John's not his biological father]]. She is furious when Elly starts to snap out of it and realize that Connie's a PoisonousFriend, [[spoiler:and that, combined with WomanScorned, caused her to kill Elly.]]
* The BLU ponies in ''Fanfic/WakingNightmares'' are trained killers with all sorts of mental hangups (Medic proudly admits to being a dedicated sadist, Sniper and Spy bring up their skills at assassination with pride, and Pyro... well.) but they are wholly dedicated to protecting their new Ponyville friends, and their dangerous skills are needed against the growing threats. It still makes the others a bit uncomfortable when they're reminded.
* In ''Fanfic/NecessaryToWin'', Maho [[DefiedTrope defies this trope]]. Miho's happiness is her primary motivation, and to fulfill this, she chooses to be Nishizumi heiress so that Miho will not have to. However, she is unwilling to use any tactics that Miho would not approve of, especially those that involve putting others at risk of harm.
* Umbra towards Erin in ''Fanfic/AndTheStoryContinues''. Umbra is a PsychopathicManchild of a shinigami who's been in love with AllLovingHero Erin [[StalkerWithACrush since he first saw her]] [[spoiler:[[ResurrectedRomance (again)]]]]. Calling himself her "friend forever," he eventually defects to the heroes' side [[MoralityChain mainly for her sake]] and is a very useful ally; [[spoiler:he even tricks another shinigami into granting her immunity to the Death Note]]. But he torments her all the while without meaning to. For one, he has no problems with committing murder (such as in retribution when [[spoiler:Kimiko accidentally kills Erin's cat]]), whereas Erin firmly believes ThouShaltNotKill. For another, he's [[CrazyJealousGuy extremely possessive of her]], to the point of openly harassing Stephen when he notices how close they're getting, fearful that she'll stop loving him with this new guy "stealing" her attention.

* Pete in ''Film/AGoofyMovie''. Whereas in ''WesternAnimation/GoofTroop'', Pete was just a heartless {{jerkass}} who only cared about himself, the film version of Pete wants to legitimately help Goofy raise Max better. The problem is that Pete is very cynical and condescending, especially towards children of any age, so Pete just assumes Max is bad and works from there. [[spoiler:And while [[JerkassHasAPoint Pete turns out to be right about Max changing Goofy's map]], Pete never suggests that Goofy talk to his son, just punish him so Max doesn't talk back.]]
* The Operative in ''Film/{{Serenity}}'' fills this role for the controlling central government. He himself observes that the purpose of his actions is to maintain an ordered society for people unlike him. In the end [[spoiler:he finds out that the government has terribly failed to uphold its ideals, so he ceases to work for it.]]
-->'''Operative''': I believe in something greater than myself. A better world. A world without sin.\\
'''Malcolm''': So me and mine gotta lay down and die so you can live in your better world?\\
'''Operative''': I'm not going to live there. There's NoPlaceForMeThere... any more than there is for you. Malcolm, I'm a monster. What I do is evil. I have no illusions about it but it must be done.
* Tyler Durden very much fits this trope in ''Film/FightClub''.
-->I'll bring us through this. As always. I'll carry you, kicking and screaming, and in the end you'll thank me.
* Nicky Santoro in ''Film/{{Casino}}'' is the source of all of Sam "Ace" Rothstein's problems. Rothstein was a powerful, rich, and successful casino manager and lost it all due to the attention the mobster Nicky kept drawing to him. ''Casino'' is actually based on a true story though names were changed for the film.
* Sean Penn's character (a lawyer turned gangster) was the poisonous friend to Al Pacino (a former gangster trying to go straight) in ''Film/CarlitosWay''.
* ''Film/MeanStreets'': Johnny Boy is this to Charlie.
* In [[Series/MysteryScienceTheater3000 MST3K]]'ed film ''Film/TheBruteMan'' The Creeper is willing to kill to take care of the blind pianist Helen.
* Another [=MST=]ed movie, ''Film/TheBeatniks'', has [[LargeHam Mooney]], who absolutely refuses to let Eddy break away from the gang to start a singing career.
* Withnail in ''Film/WithnailAndI'' absolutely ''revels'' in this trope.

* Dolores Umbridge in ''Literature/HarryPotterAndTheOrderOfThePhoenix'' knows that Cornelius Fudge would never permit her to [[spoiler:use the torturous Cruciatus Curse to get information out of Harry and his friends]], but as she says, "What Cornelius doesn't know won't hurt him". Even the book synopsis on the dust cover describes Umbridge as having "a personality like poisoned honey."
** The secret of Dumbledore's childhood: [[spoiler:his poisonous ([[WordOfGay boy]])friend Gellert Grindlewald.]]
** In a more complex way, and probably not intentionally, it's Snape for Dumbledore, being the Bad Teacher for Harry (Dumbledore obviously being the good one). His constant nitpicking, bickering and sneers served to harden Harry's spirit and supposedly not to get a swelled head. Not that it was pleasant, or remotely useful, given that Harry [[HumbleHero hated the fame from the beginning]] and already had to go through the traumatic experience of being a murder target almost every year.
*** Not that it was ''successful'', either, since not only did Harry already arrive at the school detesting excessive fame and attention thanks to the Dursleys' treatment, Snape's treatment also caused Harry to constantly suspect Snape of evil through all of the books, which almost allowed Voldemort to win several times (a notable example being the first book, where Harry attempting to prove the wrong person guilty gave the ''real'' Voldemort ally too big of a lead).
* [[Literature/TheBible The Biblical figure]] of Joab in Second Samuel. As King David's general he frequently performs David's dirty work including orchestrating the death of Uriah the Hittite (on David's orders) so David may marry Uriah's widow, Bathsheba, and executing David's son Absalom for rebellion, against David's orders. While Absalom's death enables David to remain king, David publicly mourns for Absalom, and eventually orders Joab to be killed.
** Even then, David didn't technically give the order. Solomon gave the order on his behalf, after yet another betrayal and David confiding in him about Joab's past actions.
** For another poisonous friend in the Bible, try Jezebel. She led Ahab to worship false gods, and had the prophets of the God of Israel killed, as well as those who worshiped the true God. After several years of perversions, lies and murder, things eventually came to a head. Her husband (and the King of Israel), Ahab, wanted the vineyard of Naboth. Naboth refused to sell, despite good offers of money and better land elsewhere. Jezebel had Naboth killed on trumped-up charges of blasphemy against God and the King, thanks to two false witnesses she paid off.
** God sent Elijah to talk to Ahab, as he went to take Naboth's field. Elijah cursed Ahab and Jezebel as enemies of God: both were eventually killed, Ahab in battle, and Jezebel by being tossed out of the window.
* In Patrick O’Brian’s Literature/AubreyMaturin novels, the dual protagonists are frequently ''each other’s'' poisonous friend: each man has been known to aid his dearest friend’s missions by conducting hostilities in ways that are appalling to the latter’s sensibilities or morality--the swashbuckling captain Jack Aubrey with large-scale naval carnage, the surgeon/intelligence agent Stephen Maturin with cold-blooded assassination and deception.
** Maturin also [[ArsonMurderAndJaywalking reads other people's mail]]. Aubrey is not cool with that.
*** And, on the flip side, while Aubrey is by no means a "[[BadBoss flogging captain]]" he uses the lash sometimes, much to Maturin's displeasure.
* The novel ''Shady Corners'' by Mathew Williams has a PoisonousFriend as the ''protagonist''. It's every bit as creepy a read as you'd expect.
* In ''Literature/TheBabySittersClub'', Ashley, who encouraged Claudia to leave the club and spend more time on her artwork. Also the "bad girls" group that Stacey falls in with later in the series.
* In ''Literature/TheGeneral'', Suzette, Lady Whitehall. Wife of the straightforward and honest Raj Whitehall, who survives the Byzantine machinations of the Governor's court despite his total lack of aptitude for such things... because Suzette is entirely happy to seduce and manipulate his rivals, poison his enemies, and arrange for obstructionist officials to be quietly dropped into the river with a sixty-kilo roundshot chained to their ankles. All without telling him. Disturbing because he is WELL AWARE of what she is doing and yet is on occasion preachy about the morality of doing it.
* The whole purpose of [[Literature/TheCulture Contact's]] ''Special Circumstances'' division.
* Rare protagonist example: [[Literature/TheDresdenFiles Harry Dresden]] to Michael Carpenter, his good friend, who is a (literal) KnightInShiningArmor and has an uncompromisable code. So, in ''Death Masks'', he asks Michael to leave the room while he [[ColdBloodedTorture breaks the legs]] of Quintus Cassius.
** And then Ebenezar is something of a PapaWolf Poisonous Friend to Harry. [[spoiler:Blackstaff, anyone?]]
** Lasciel acts like a poisonous friend to her hosts in order to corrupt them.
* Perrin's loving girlfriend and wife Faile in ''Literature/TheWheelOfTime''. Besides being a very jealous type and giving him a hard time over any woman she suspects might want him, she also indulges in all the dirty aspects of politics he considers to be wrong, including sabotage, espionage, manipulation and assassination. Some of those things he tells her not to do, but she doesn't listen. The rest, he chooses not to ask about or think about too closely.
* [[TheFairFolk The Gentleman with the Thistledown Hair]] in ''Literature/JonathanStrangeAndMrNorrell'' gets it into his head that working as a butler constitutes abuse for Stephen Black, and decides that because he's handsome and courteous, he needs to be king of something. He even tries to get him to [[YouKillItYouBoughtIt kill the king of England for this reason]], and Stephen has to explain that it doesn't work like that.
** There's a dark sort of OverlyLongGag late in the book where The Gentleman tells Stephen a rambling story of the lengths he went through to find Stephen's "true" name and the many people he ended up murdering directly or indirectly in the process.
* Vimes and Vetinari in ''Literature/{{Discworld}}''. Unusual in that the PoisonousFriend is actually the protagonist's boss.
** Vimes's butler Willikins is this to Vimes. He has been for a long time, but as of ''Snuff!'' he identifies as such.
* Lord Montfallcon does this for a living in ''Gloriana'' by Creator/MichaelMoorcock, working behind the scenes to maintain order because he fears his queen's idealistic policies aren't enough to secure the realm's new golden age.
* Valentinian in Literature/BelisariusSeries has some aspects of this; not only is he Belisarius' bodyguard, he is his personal executioner and hatchet man. When Belisarius wants some shocking bit of violence done he simply says "Valentinian..." which is shorthand for OffWithHisHead.
* Monk Mayfair is just short of this to Franchise/DocSavage. Creator/PhilipJoseFarmer theorizes that in addition to Savage needing someone who can kill (and lie, steal and seduce), Mayfair's obvious enjoyment of these gives Savage vicarious pleasure.
* The ''Literature/KnightAndRogueSeries'' has a mild example in Fisk. While Michael is so righteous that he won't even tell a white lie, and encourages Fisk to follow this example, Fisk is willing to lie or con his way out of a situation when need be-usually when Michael isn't looking. He becomes less of one by the third book, though.
* The CorruptCorporateExecutive Cassandra Cautery is all kinds of this to Dr. Charles Neumann in Max Barry's ''Literature/MachineMan''. She claims to have his best interests at heart, but is clearly only looking out for Better Future.
* Creator/StephenKing's thriller ''Thinner'' gives us an anti-heroic example: Protagonist Billy Halleck is cursed to die by a pack of traveling Gypsies after accidentally killing the leader's daughter. Billy's best friend, mafioso Richie Ginelli, responds by poisoning their guard dogs, shooting up their camp (without killing anyone), and assaulting the clan leader's granddaughter. The old leader takes the curse off, but Ginelli is killed by said granddaughter in the end.
* From the novel ''Literature/{{Surrender}}'', Finnegan is this to Gabriel.
* In ''Literature/ASongOfIceAndFire'', being Cersei Lannister's enemy is a hassle, but being her friend is, arguably, even worse. Everyone she has ever associated herself with has suffered for it. Even if Cersei means well going in ([[FalseFriend she doesn't always]]), she's still at heart a [[{{Narcissist}} narcissistic]], [[SmallNameBigEgo overly-proud]], [[EntitledBastard entitled]], [[PsychopathicManChild overgrown]] RoyalBrat with a tendency towards [[TheAlcoholic alcoholism]] and BlackAndWhiteInsanity. So, even if she likes somebody, she'll wind up screwing them over with it because she just can't do healthy relationships. Even with best intentions.
* Captain Badaya ''would'' be this to Admiral Geary in later volumes of ''Literature/TheLostFleet'' series, leading a faction of the fleet that would back him in a full-blown coup... except that Admiral Geary, who's considerably smarter than Badaya as well as TheIncorruptible, successfully bluffs him into thinking he's blackmailed the government into making him TheManBehindTheMan instead.
* [[AlphaBitch Zadie Smith]] of ''Literature/ReconstructingAmelia'' is this to her best friend Dylan, who's sweeter, more quiet, and has a much harder time standing up for herself -- including standing up to Zadie. Zadie genuinely cares for Dylan... and this drives her to [[spoiler:out her girlfriend Amelia, which indirectly leads to Amelia's death]], for Dylan's "own good." Rather than humanizing Zadie, their friendship makes Zadie ''[[TeensAreMonsters terrifying]]''. It doesn't help that there are some [[AmbiguouslyGay undertones]] that imply that [[spoiler:Zadie hates Amelia because she [[ClingyJealousGirl wants to]] [[IfICantHaveYou keep Dylan]] [[{{Yandere}} all for herself]].]]
* [[TheJeeves Jeeves]] of ''Literature/JeevesAndWooster.'' Frequently puts others, including Bertie himself, through the wringer in order to restore [[StatusQuoIsGod the status quo]], and has been known to interfere in Bertie's relationships and deliberately drive away prospective fiancées--all for his own good, of course.
* In ''Literature/{{Victoria}}'', John Rumford becomes one to President Yancey, General Laclede and the other Neo-Confederate leaders through his ruthless solution to the Atlanta insurrection, which he then gives them credit for.

[[folder:Live Action TV]]
* Jimmy [=McNulty=] in ''Series/TheWire'' is likeable, witty, fairly moral for a Baltimore city police, and one of the best detectives in the BPD. Sadly, he has a habit of backstabbing his colleagues in order to get results and wildly breaking the rules, to the point that nearly every detective ends up having to do some serious fighting to hold onto their careers after one of [=McNulty=]'s crazier/stupider plans goes [[DidntThinkThisThrough disastrously wrong.]]
-->'''Michael Crutchfield''': Did [[=McNulty=]] fuck you?
-->'''Bunk Moreland''': He tried. But mostly he just fucks himself.
* Bebe on ''Series/{{Frasier}}'' was a classic example of this: the completely unscrupulous agent. Frasier was frequently warned that agreeing to anything she suggested, however favourable and seemingly innocent, was tantamount to [[DealWithTheDevil dealing with Satan]].
-->'''Frasier''': What kind of a woman are you? You seduced me, you lied to me, you nearly got me killed. You've shamelessly manipulated not only me but the station, the news media, and the entire city of Seattle. What do you have to say for yourself?
-->'''Bebe''': Aren't you glad I'm on your side?
* Saul Tigh on ''Series/{{Battlestar Galactica|2003}}''. He's best friend to Commander/Admiral Bill Adama (Galactica's resident beloved leader). He's usually the guy rooting for a good fight rather than diplomacy, and occasionally, is right in doing so. But he's a liability. Time after time after frackin' time, Adama goes out on a limb for Tigh - hiding the truth of his alcoholism, appointing him XO even though he's "not cut out for command", and whitewashing, then forgiving, most of Tigh's screwups (including shooting civilians aboard the ''Gideon'', a military dictatorship, the use of suicide bombers on New Caprica, and showing up drunk to testify at Baltar's trial). Though he occasionally has to ShootTheDog to keep the blood off Adama's hands (see the entire New Caprica arc and the S3 episode "Hero"), one shudders to think how far [[spoiler:a Saul Tigh who's realized he is, in fact, the very thing he's been fighting for so long]] will go in the service of Bill Adama.
** In an odd case, Tigh himself has his wife Ellen, who encourages his alcoholism and tries to get him to be more assertive and ambitious. And betrays resistance plans to the Cylons to keep him alive. [[spoiler:However all of this is now in the past tense as he poisoned her for this last. Supposedly someone else in the resistance would have done something worse to her otherwise]].
*** He is this way up until [[spoiler:he learns that he is a Cylon]]. It is very likely his destructive behavior and drinking were his way [[spoiler:of internally dealing with his "sleeper" status, and keep himself from doing something fatal to Galactica and Adama]], but YMMV...
* In ''Franchise/StarTrek'', "Section 31" performs questionable actions in (preemptive) defense of the Federation. Played with a bit, as when they first surfaced in ''[[Series/StarTrekDeepSpaceNine Deep Space Nine]]'' the Federation was actively trying to shut them down; ''Enterprise'' sort-of retconned them into originally being the black-ops wing of Starfleet Intelligence, and apparently losing their budget and official status at some point seems not to have slowed them down much.
** Garak proudly admits to being this trope in "In the Pale Moonlight":
--> ''That's why you came to me, isn't it, Captain? Because you knew I could do those things that you weren't capable of doing? Well, it worked.''
** [[spoiler:Tuvok]] cites this trope as his reason for secretly betraying Captain Janeway in an early episode of ''Series/StarTrekVoyager'', saying that his role requires making the morally dubious choices she can't make in order to get the crew home. She doesn't take it well.
** Section 31's official status is also listed in the non-canon ''Section 31'' novels, where Kirk carefully reads the Starfleet Charter and locates Article 14, Section 31, which is a short clause allowing for the creation of an unspecified agency with unspecified powers to safeguard humanity.
* ''Series/DoctorWho'':
** Leela has no qualms about violently disposing of anything or anyone that threatens the Doctor, despite his many attempts to rein her in.
** Captain Jack Harkness is willing to go quite far to protect the Doctor, using methods that the Doctor would never approve of.
** River Song takes this trope UpToEleven, willing to [[spoiler:let time itself be destroyed]] just to keep the Doctor alive. It frustrates him terribly. On the the other hand, he does admit that her methods are useful at times:
---> '''The Doctor''': Oh, and this is my friend River. Nice hair, clever, has her own gun. Oh, and unlike me, she ''really'' doesn't mind shooting people. I shouldn't like that. Kinda do, a bit.
--->'''River:''' Thank you, Sweetie.
*** Neatly summarized when River faces a Dalek:
----> '''Dalek:''' [[AC:Records indicate you will show mercy. You are an associate of the Doctor.]]
----> '''River:''' I'm River Song. Check your records again.
----> '''Dalek:''' [[AC:Mercy!]]
*** She gets it from her mother:
----> '''[[spoiler:Amy]]''': River Song didn't get it all from [[EvilMatriarch you]], "sweetie".
----> '''Madame Kovarian''': **Death wail**
** Missy. She's "I'b helpig" homicidally insane.
---> '''Missy''': (After chaining Clara to a wall of undead Daleks as bait, poking holes in a Dalek, then letting the undead Daleks swarm the unfortunate Dalek) Wheee!
* ''Series/BuffyTheVampireSlayer'': Giles on several occasions, in particular beating the crap out of Ethan in "Halloween", killing Ben in "The Gift", and plotting with Robin to kill Spike in "Lies My Parents Told Me". And [[spoiler:sending Faith to kill Gigi]] in the Season Eight comics.
** He even gives a nice speech about it in "The Gift".
--->'''Giles:''' No she couldn't [have killed you]. Never. And sooner or later Glory will re-emerge, and make Buffy pay for that mercy—and the world with her. Buffy even knows that, and still she couldn't take a human life. She's a hero, you see. She's not like us.
--->'''Ben:''' ... Us?
--->'''Giles''' (''calmly suffocates Ben'')
** Believing that Buffy is compromised by her love for Angel, Xander tries to ensure his demise on two separate occasions, "Becoming, Part Two" and "Revelations", first by not telling Buffy that Willow was working on a spell to restore his soul, then by encouraging vampire Slayer Faith to kill Angel after he'd come back from the dead.
** Really, all of the cast for [[Series/BuffyTheVampireSlayer both]] [[Series/{{Angel}} shows]] are this for all the others (besides Dawn, Tara and Lorne). We've seen them all without the others (Wishverse Buffy, Dark Willow, Ripper, Angel after firing everyone, Wesley after his betrayal) and they're all much, much worse without the others. So it's like ConservationOfNinjitsu, only with evil.
** In a subversion, when Fred plans to murder (or at least trap inter-dimensionally, which probably a death sentence) her old college professor, who did the same to her and at least four other people, her boyfriend Gunn kills him for her, in an attempt to fulfill this trope. Fred does not take this well at all.
* On ''Series/{{Charmed}}'', Cole kills a [[CorruptCorporateExecutive corrupt landlord]] who is trying to blackmail Phoebe. This is a turning point in one of his [[HeelFaceRevolvingDoor several backslidings into evil]].
* ''Series/BurnNotice'' plays with this trope. Michael is hardly a boy scout himself, but it's implied in several episodes that hanging out with a HandsomeLech FBI informant and AxCrazy arms dealer and former IRA terrorist are not exactly helping his standing with the intelligence community.
** Conversely, Sam and Fi are portrayed as good influences compared to some of the people Michael has had to [[FoeYay get into]] [[IncrediblyLamePun bed with]] in the course of investigating the people who burned him. A particularly strong example is Larry, Michael's former mentor-turned-PsychoForHire ProfessionalKiller, who's always showing up trying to convince Michael to join him. In a sort of [[InvertedTrope inversion]], Larry thinks that Michael's true potential is [[TheyWereHoldingYouBack being stifled]] by his association with his present comrades.
* ''Series/TheGoodWife'' includes Fred Weller guest starring as a {{jerkass}} AmoralAttorney. It's implied he acts this way in part because he believes his boss deserves someone watching his back and willing to get their hands dirty. Good thing, too, because it was the only thing giving his character depth. [[spoiler:Too bad his boss doesn't deserve it . . .]]
* On ''Series/{{Luther}}'', the eponymous Scotland Yard detective has Alice Morgan, a former ChildProdigy who brutally murdered her parents and got away with it, and has now developed a crush on the copper who investigated the case. Luther really doesn't appreciate her attempts to help him get back together with his estranged wife, which seems to involve a lot of breaking and entering and assault.
* [[VillainProtagonist Walter White]] is this to [[AntiVillain Jesse Pinkman]] in ''Series/BreakingBad''. While Jesse wasn't completely innocent before getting into business with Walt, it's undeniable that his life has taken a definite [[BreakTheCutie turn for the worse]] because of Walt's influence. [[spoiler:Walt even manages to manipulate Jesse into killing Gale in cold blood.]] Jesse is equally poisonous to Walt, if usually unintentionally, and in a completely different way: while his sincerity might be debatable, we continue to see Walt go to impressive lows in order to ensure Jesse's safety, despite the fact that he is an emotionally volatile wild card and a liability. Add this to the fact that Jesse is the one who gets Walt into the drug business in the first place, and you have a recipe for one of the most mutually poisonous friendships on television. One so toxic, it has a collateral death count of [[spoiler: close to a hundred, if not ''in'' the hundreds]].
* Series/{{Revenge}} has Nolan, who's actually an inversion of sorts: while he assists Emily Thorne in her titular revenge gladly and is significantly more cynical than she is, he also frequently points out she could easily just go off to enjoy her life and leave the people who wronged her behind.
* The ''Series/CriminalMinds'' episode "The Performer" [[spoiler:has the unsub turn out to be Dante/Davies's manager using an obsessed, schizophrenic fangirl to murder other fans to get publicity for his new album. Davies is quite horrified at this.]]
* In an interesting SitCom variant, Lily from ''Series/HowIMetYourMother'' is revealed to be this, breaking up Ted's girlfriends if she thinks that it will be better for Ted (and, by extension, herself).
* [[FullyEmbracedFiend Damon]] of ''Series/TheVampireDiaries'' can sometimes fall into this role, particularly in regards to protecting Elena. He's outright stated that he will do whatever he has to do in order to keep her safe, even if she hates him for it.
* ''Series/{{Scandal}}'': Pretty much the entire main cast are this to each other. Olivia and Cyrus will do horrible things to protect President Fitzgerald Grant and in turn Grant will do horrible things to protect Olivia. Melly Grant will do anything to protect her husband, even though she knows that he loves Olivia, because she made it her life's mission to get Fitz elected president. Olivia's Gladiators do increasingly nastier and nastier things to protect Olivia and each other. B6-13 is an entire secret government agency that is the poisonous friend for the United States, torturing and assassinating people, and even committing acts of terrorism in order to secure the well being of the country.
* ''Series/PrettyLittleLiars'': Alison is a deconstruction, as her behavior actually drives the Liars away from her. CharacterDevelopment makes her less of one as the series goes on, though.
* ''Series/TheFlash2014'' has Harrison Wells, Barry's mentor who is helping him learn how to control his powers. He's willing to go to great lengths to keep Barry safe, including [[spoiler:killing Simon Stagg and leaving General Eiling to the mercies of Grodd,]] because both of them had their own designs on the Flash.

* "Pet" by Music/APerfectCircle is about this.
-->Pay no mind what other voices say
-->They don't care about you, like I do, like I do
-->Safe from pain and truth and choice and other poison devils,
-->See, they don't give a fuck about you, like I do.
-->Just stay with me, safe and ignorant,
-->Go back to sleep...

[[folder:Tabletop Games]]
* In the ''TabletopGame/{{Ravenloft}}'' setting for TabletopGame/DungeonsAndDragons, Wizards can summon a familiar and paladins can summon a war horse, like in other settings. However, these companions are AlwaysChaoticEvil (or lawful evil or neutral evil, depending on the law/chaos alignment of the summoner) in Ravenloft. They are loyal to their master, but lack a conscience, and aren't averse to carrying out evil deeds to "help" their master behind his back. This is bad enough for wizards, but potentially devastating for a paladin, who now has to deal with a pet that constantly puts him in danger of losing his paladinhood.

* JustForFun/TheZerothLawOfTropeExamples, and subverted and lampshaded as well! In ''Theatre/AntonyAndCleopatra'', when Pompey the Younger has made peace with Octavian, Mark Antony, and Lepidus, his subordinate Menas suggests [[NastyParty taking advantage of their celebratory drunkenness]] to kill them all. Pompey's response can be summarised as "As an honourable man, I have to forbid you from doing any such thing. SO WHY DIDN'T YOU JUST DO IT?". This incident was taken directly from Plutarch.

[[folder:Video Games]]
* [[DoubleSubversion Doubly-subverted]], {{deconstructed}}, and mixed in with a little PsychoSupporter in ''Videogame/{{Brink}}''. TheResistance has some [[WellIntentionedExtremist rather extreme followers who are willing to do ''anything'' if they think it will help Brother Chen and the Resistance.]] [[LampshadeHanging At one point, one of them says that they will do the dirty work while Brother Chen, the much more reasonable leader of the Resistance, will be able to keep his hands clean.]] The {{subversion}} comes when Chen mostly tolerates such soldiers, since he sees them as necessary for the war effort and for his political promotion. Its {{deconstructed}} through Moekena, who looks at Chen and the radical followers and sees a vile leader who uses others so that he doesn't get his hands dirty instead of seeing a conflicted leader who has to deal with dangerously extreme but necessary followers, since Moekena does not know of Chen's point of view. Its doubly subverted when [[spoiler:Chen yells at the radical followers in rage once they attempt to cover [[DownerEnding (or succeed]] [[TheBadGuyWins in covering)]] the Ark in nuclear fallout for him in a [[MultipleEndings What-If mission,]] calling the radicals idiots and rebuking them for not realizing that he was bluffing.]]
* ''VideoGame/Disgaea3AbsenceOfJustice'': Princess Sapphire has some interesting ideas on how she should help Almaz once she learns of his predicament. Most of them involve [[MurderIsTheBestSolution killing someone]], as [[AxCrazy almost all of her ideas do]]. That said [[spoiler: she and Almaz end up married at the end of the game]], so she does grow out of it, at least where he's concerned. Given the fact that [[spoiler: his temporary death]] is the first thing in a LONG time that causes her to cry, it's shown how much she does actually care. She wasn't even able to cry at her mother's funeral.
** Mao's butler Geoffrey is a Poisonous Underling, manipulating events behind the scenes to [[spoiler: make Mao the perfect EvilOverlord so that he, in his true identity as the Superhero Aurum, can have a WorthyOpponent to battle]].
* Soren in ''[[Franchise/FireEmblem Fire Emblem: Path of Radiance]]'' toes the line of this, acting as Ike's second in command and advisor. Cold, hyperrational, and only caring about Ike, he discourages the more sentimental decisions. But he doesn't take this trope to its fullest extent, as he doesn't make any unsavory choices behind Ike's back.
%%* Alexa in ''[[VideoGame/CommandAndConquerTiberiumWars Command & Conquer 3: Kane's Wrath]]''.
* Axel to Roxas and Xion in ''Franchise/KingdomHearts''. He seems like a pretty cool guy, and he genuinely cares about his friends, but a single playthrough of ''Chain of Memories'' is more than enough to see how wickedly treacherous he can be. This becomes even more apparent towards the end of ''358/2 Days''. He grows so attached to Roxas and Xion that he becomes obsessed with maintaining their friendship and keeping them safe -- however, to achieve this, he lies to them, does questionable stuff behind their backs, and if they try to leave the Organization of their own free will, he attempts to bring them back by force. Things come to a terrible head when Roxas finally gets fed up with this and [[spoiler: deserts the organization,]] and Xion ends up initiating a [[spoiler: SuicideByCop that results in her wiped from existence]]. Axel does redeem himself in the end, but [[spoiler: RedemptionEqualsDeath]]. Although, since he's [[spoiler: now BackFromTheDead in the form of his original self]], its possible that he can finally make his actions speak for it.
* [[spoiler:[[WellIntentionedExtremist Mithos]] is a poisonous ''brother'' of Martel]] in ''VideoGame/TalesOfSymphonia'', whose [[spoiler:misinterpretation of Martel's wish for a discrimination-free world leads to him attempting to execute an AssimilationPlot.]]
* Sodia from ''VideoGame/TalesOfVesperia''. [[spoiler:She tries to [[MurderTheHypotenuse murder Yuri]], whom ''she'' perceives as Flynn's poisonous friend.]]
* ''VideoGame/WorldOfWarcraft'':
** Makuru is one to Obadei, insisting on taking vengeance against the orcs after learning that they killed Obadei's brother.
** In ''Mists of Pandaria'', Wrathion is shaping up to be this. He believes the Burning Legion will eventually invade Azeroth, so the Alliance/Horde war must end so that Azeroth can put up a unified front against the threat. However, being a black dragon, Wrathion's idea of world peace involves one of the two factions conquering the other. Pretty much everyone else who meets him agrees that Wrathion should not be trusted.
* In ''VideoGame/DragonAgeOrigins'', Morrigan kind of fits this, since she approves of the Warden's more ruthless actions and dislikes his/her more compassionate ones. However, if the Warden makes an effort to befriend her, she is steadfastly loyal, even deeming a female Warden to be an honorary sister of sorts.
** A better example appears on the antagonists' side: Arl Howe to Teryn Loghain. Arl Howe does seem genuinely loyal to Loghain and his political and military support is a great boon to him as well. However, Loghain supporting him and making him Arl of Denerim will help to screw him over in the Landsmeet if you bring up some of Howe's actions [[spoiler:like kidnapping and torturing the son of another noble.]]
* ''VideoGame/DragonAgeInquisition'' turns [[TheHeart Leliana]] into one, blood loyal to her allies, but utterly ruthless. Indeed, she spies on her best friend [[ActualPacifist Josephine]] trying to resolve her family problems, before proposing going behind her back and resorting to infiltration and assassination, knowing full well it will get a WhatTheHellHero reaction but happy to shoulder that burden if allowed.
* Kreia in ''VideoGame/KnightsOfTheOldRepublicIITheSithLords'' qualifies. She has an obsessive and controlling attitude toward your character, vehemently opposing the addition of most of your party members and any associations with [[NonPlayerCharacter NPCs]] who seem to threaten her hold on you. One major difference is that, rather than try to keep you [[TheCape pure]], the lessons she imparts to you as your [[EvilMentor mentor]] are usually geared toward you becoming a ManipulativeBastard: in conversation, a manipulative response that takes long-term goals into consideration is usually the way to make her happy. Bonus points if you choose TheDarkSide, as most of your party members who care enough about you to try to intervene attribute it to [[ToxicFriendInfluence Kreia's bad influence on you]].
* Depending on how moral you want to play it, Steven Heck is this to Mike in ''Videogame/AlphaProtocol'', murdering and framing innocents to help his buddy.
* In ''VideoGame/{{Disgaea 4| A Promise Unforgotten}}'', Fenrich vowed to make the vampire tyrant Valvatorez the greatest in all the Netherworld. The only problem? Somewhere along the line, Val [[FriendlyNeighborhoodVampire seems to have developed some sort of pesky conscience]], [[VegetarianVampire has sworn off human blood]] (which has massively {{De Power}}ed him), and has insisted on following a new code of evil [[NobleDemon which is not very evil at all]]. Fenrich has no intention of giving up his original vow, so...
** Some of Fenrich's ideas tend to cross a few moral lines ([[MoralEventHorizon but never THAT one, thankfully]]). During Chapter 5, he goads Valvatorez into promising him that he will take down Vulcanus should she pose an obstacle to their plans... and then goading ''her'' into a fight with them by blowing their bounty out of proportion. ''Right in front of Valvatorez!''
* In the first ''VideoGame/GodOfWar'', Ares honestly seems to think he did Kratos a ''favor'' when he tricked him into murdering his own family. During their final battle, Ares throws a fit and claims that Kratos had no right to turn against Ares after everything Ares did to make him stronger. At the end when Kratos has Ares at his mercy, Ares makes one last plea for his life by telling Kratos that he just wanted to make Kratos a great warrior. [[GoneHorriblyRight Unfortunately for Ares, he succeeded.]]
* ''Franchise/MassEffect'':
** Commander Shepard is accused of being one, albeit unintentionally, by Admiral Rael'Zorah in ''Mass Effect 2'' due to Shepard's return for the dead causing his daughter, Tali, to nearly immediately file a transfer request to join them on what is essentially a ''suicide mission''.
** Matriarch Aethyta gets in on this in ''Mass Effect 3'', noting that Shepard's influence has lead to Liara dealing with some severely sketchy people in the last 3 years. Considering Liara spent the past 50 years beforehand as an archaeologist working alone on dig-sites, which Liara herself noted have ''less explosions'', Aethyta definitely has a point.
** Cerberus as a whole is humanity's poisonous friend initially. Much like Section 31 described above, they too started as a black ops unit then went their own way. Some of the questionable things they are involved in - cloning rachni to act as shock troops, attempting to repurpose Thorian creepers as shock troops, even attempting to repurpose [[NotUsingTheZedWord husks]] as shock troops, siccing thresher maws on troops to study them, injecting a human soldier with thresher maw acid to see if it will turn him into a super soldier, kidnapping humans and aliens for horrific biotic experiments, plugging in autistic savants to an AI neural network to try to control it, and finally running an extermination camp to study Huskification with the ultimate goal of subjugating and enslaving the [[BigBad Reapers]]. All of these things were done to protect or advance humanity.
* Introduced in ''VideoGame/DynastyWarriors 8'', Jia Chong is this to the easygoing Sima Zhao. It's made quite explicit - while Sima Zhao looks (and acts) like a Californian surfer transposed into ancient china, Jia Chong is [[EeriePaleSkinnedBrunette pale as death with hair as black as night]]. Several soldiers refer to the two as being 'like light and shadow'. Jia Chong repeatedly takes action to benefit Sima Zhao, usually without bothering to check with him first, and is particularly swift to kill off enemies that Sima Zhao seems inclined to offer mercy to. Culminating in...
-->'''Sima Zhao''': ''(Standing with his sword raised over the Wei Emperor)'' This is what you want from me, right?!
-->'''Jia Chong''': Yes... but the dirty work is my job. ''(Cuts down the Emperor himself)''
* ''VideoGame/ShadowHearts'' gives us Arcane Olga, a sadistic witch's ghost who cackles as she drains the life out of innocent civilians. She is later recruited by the BigBad, who is a SophisticatedAsHell AntiVillain. She is working for him because she admires him and will reign in her sadism based on his orders, however if he doesn't specifically order her otherwise she goes right back to hurting people for the fun of it.
* The ''VideoGame/BatmanTheTelltaleSeries'' has "John Doe", aka SelfDemonstrating/TheJoker, who manages to be this to Bruce. He's a violent and unsettlingly creepy lunatic who derives cruel pleasure from fighting, mayhem, and destruction, but at the same time he's a truly loyal friend to Bruce who genuinely cares about him, even ''saving his life'' at a couple key points in both Seasons. He manages to be simultaneously an innocent victim of mental illness as well as ''scary as hell''.

[[folder:Visual Novels]]
* Rider is [[spoiler:Sakura]]'s poisonous friend in the Heaven's Feel route of ''VisualNovel/FateStayNight''. She's willing to let the world be destroyed or kill [[spoiler:Shirou and Tohsaka, her sister,]] just to prolong her life an extra couple days if she has to, whether Sakura wants her to or not. Eventually, she realizes that [[spoiler:Sakura]] just being ''alive'' isn't sufficient, and ends up fighting against her. She's still acting almost exclusively for Sakura's benefit, though.
** Shinji, Sakura's [[spoiler:adoptive, abusive]] brother is this for Shirou.
* In ''VideoGame/{{Hakuouki}}'', Hijikata Toshizo intentionally takes on the role of harsh disciplinarian and "Demon Vice-Commander" to keep order within the Shinsengumi and further Commander Kondou Isami's goals against the heavy opposition of the era's very classist society, allowing Kondou to remain as nice and brotherly and idealistic as he wants to be. It's a mild example since Kondou is aware of everything Hijikata is doing, but there are points at which Hijikata is specifically noted as "playing the villain" for Kondou's sake. [[spoiler:In the end, it kind of backfires on both of them, as Hijikata's efforts protect Kondou from many of the harsher realities of leadership and leave him unprepared to deal with the situations the Shinsengumi face after the Boshin War begins.]]
* ''VisualNovel/HatofulBoyfriend'' has two notable examples, both revealed in the much darker "Bad Boys' Love" route. [[spoiler:Namely, Hitori Uzune's efforts to avenge (and later, [[{{Yandere}} keep the remains of]]) his brother Nageki Fujishiro, and [[WouldHurtAChild the extremes to which]] Yuuya Sakazaki went to protect his brother Sakuya Shirogane Le Bel.]]

* ''Webcomic/LookingForGroup'': Richard. Just... Richard. Cale has conceded that Richard is both a blight upon the world and the best chance they have at saving it, IF he gets enough material to troll Cale with when the party isn't looking. And by material we mean knights, peasants, orphans, endangered animals, funny dogmatic armies, doggy funmatic MixAndMatchCritter, etc.
** Pella commits a crime to further the main character's cause.
* ''Webcomic/SomethingPositive'': Hurt Davan in any way and [=PeeJee=] and Aubrey will respond with [[DisproportionateRetribution tenfold the pain you caused him]]. Davan is not always bothered by this.
* In ''Webcomic/MenInHats'', Aram attacks Sam with a steamroller in the name of putting Gamal's plans into action, and Gamal is pretty sure [[http://www.meninhats.com/d/20030908.html steamrolling people wasn't his idea]]. (Aram has also been known to [[http://www.meninhats.com/d/20020830.html poison]] [[http://www.meninhats.com/d/20040331.html his]] [[http://www.meninhats.com/d/20040319.html friends]], [[http://www.meninhats.com/d/20020823.html sometimes]] with [[ScaryScorpions scorpions]].)
%%* Anakin becomes this for Palpatine in ''Webcomic/DarthsAndDroids''.
* ''Webcomic/FireflyCross'' has a fairly low-key (so far) example; [[LoveableRogue Katyn]]'s friend [[spoiler:Micah]] is actually Dark, and willing to kill in order to protect her. [[spoiler:Which he's already done, when a WellIntentionedExtremist stole her [[MacGuffin sword]].]]
* In ''Webcomic/TheOrderOfTheStick'', Tarquin does seem to genuinely love Elan, but he expresses it in truly awful ways. He welcomes Elan by [[spoiler:arranging captured slaves to spell Elan's name and then burning them alive.]] He wants Elan to be happy with Haley...so he [[spoiler:frames Haley's father for murder as a "test" to see whether she deserves Elan]]. He wants Elan to grow into the role of TheHero instead of remaining a supporting character...[[spoiler:so he orders his army to kill the actual Hero Roy.]] On the other hand, being Tarquin's enemy is even worse [[spoiler:which Nale found out the hard way.]]
* Used interestingly in ''Webcomic/CobwebAndStripes'', when Betelgeuse ''offers'' to be exactly this for Lydia. He volunteers to handle anyone at her request, so she needn't get her "sweet little hands" dirty. She's not entirely comfortable with the offer, although at the same time she sort of appreciates it.

[[folder: Web Original]]
* In ''Literature/{{Worm}}'', TokenEvilTeammate Regent, realizing that SociopathicHero Shadow Stalker isn't going to leave the [[VillainProtagonist Undersiders]] alone and will in fact keep coming after them with lethal force until she gets lucky, takes it upon himself to use his PeoplePuppets power to utterly destroy her life and drive her out of town, refraining from killing her only because it would be more troublesome and draw more attention from the authorities.
* In ''Literature/{{Twig}}'', the narrator, Sylvester, becomes steadily aware that he is essentially this towards the more moral Lillian, and he worries even when they enter a romantic relationship that he isn't actually able to love her and build her up instead of tearing her down. His amorality and inbuilt ManipulativeBastard tendencies also make him worried that he'll become a poisonous influence on her future as an [[AcademyOfEvil Academy professor.]]
* In ''WebVideo/TheVeronicaExclusive'', Veronica's girlfriend Jane would do ''anything'' to make her happy, up to and including murder.

[[folder:Western Animation]]
* Beezy J. Heinous on ''WesternAnimation/JimmyTwoShoes''. In His FriendVersusLover rivalry with Heloise over Jimmy, he can get just as {{yandere}} as she can (see: "Best Bud Battle").
* WesternAnimation/{{Beetlejuice}} drags Lydia into all sorts of scams, schemes, and misadventures; however, he is profoundly loyal to her, and will utterly destroy anyone else who creates difficulties for her. (Or he would, if she'd let him. She stops him if he goes too far.)
* ''WesternAnimation/WanderOverYonder'': Although there's little doubt that [[NamesToRunAwayFromReallyFast Lord Hater]] is a bad guy, his [[TheDragon right-hand man]] Commander Peepers is largely responsible for channeling his [[EvilIsPetty unmotivated evildoing]] into a quest for galactic domination. He has been known to work behind his boss's back, as when he took out a series of bounty hunters hired by Hater to capture Wander and Sylvia, since he [[TheOnlyOneAllowedToDefeatYou wanted the credit of capturing them himself.]]
* Rick from ''WesternAnimation/RickAndMorty'', despite all the abuse, treating his family as a means to an end, and all his ''many '''many''''' flaws, will look out for his friends and family when the chips are down and isn't even sure why he bothers. Of course, since it's ''Rick'', he'll do it in some pretty ruthless, messed up, and heartless ways. Best example is when he passively protects Jerry of all people from a jealous alien out to kill him:
--> '''Message One:''' This is Garmos! I have intercepted sexual communications between you and my new girlfriend Keara! I am coming to kill you NOW!!!
--> '''Message Two:''' Yo Jerry it's the Big R. I killed that alien that was coming after ya. Looking out for you, buddy.
--> '''Message Three:''' Yo Jerry it's Rick. Don't be mad I fucked your ex-girlfriend Keara.