->''"Mouse was the truest friend I ever had. And if there is such a thing as true evil he was that too."''
-->-- '''Walter Mosley''', '''''A Red Death'''''

A trope common in private eye novels since the 1980s, and occasionally found in other genres. Sometimes, your [[TheCape morally]] [[KnightInShiningArmour spotless]] [[MartialPacifist hero]] has a buddy who's a lot less morally spotless. Often, they've been friends for so long that a bit of moral divergence hasn't spoiled it. On the more moral end of the spectrum, the friend's a HitmanWithAHeart or LoveableRogue. In DarkerAndEdgier cases, the friend is actually a PunchClockVillain, NobleDemon or even a PsychoForHire, but they deliberately avoid any situation that might actually pit them against one another because it would be [[RivalTurnedEvil just too painful]]. Of course, the friend could be just a little bit more violent or ruthless than the hero.

When this comes in useful is when the hero has to [[ShootTheDog do something that they don't feel they can do]], most often killing somebody who is certain to do horrible things to them or their loved ones or innocent bystanders, but who is too [[VillainWithGoodPublicity sneaky]] or too [[DirtyCoward unsuited]] to [[TheManBehindTheCurtain combat]] for them to be conveniently able to kill them in self-defence or some kind of [[DuelToTheDeath fair fight]]. At this point the PsychoSidekick can step in and shoot the helpless guy in the face while the hero feels some slight angst but is grateful that they didn't have to do it.

Contrasted to the case of the PoisonousFriend, in which the main character is genuinely unaware of what the friend is doing. In this case, the main character is perfectly aware of the type of person their friend is and what they do for them. Naturally, this does come across as a bit hypocritical. Sometimes the hypocrisy is ignored by the story, but more often it's lampshaded. It's sometimes explicitly or implicitly argued that the ruthless act isn't so much [[ThouShaltNotKill wrong]] ''per se'', as something that would brutalise the hero to the point that they'd lose their compassion or ability to empathise with others or [[IfYouKillHimYouWillBeJustLikeHim ability to act as a moral exemplar to others]].

Can be seen as something of an inversion of TheWatson, as in the original case of the SherlockHolmes stories, and in many others, part of the Watson's role is to smooth things over socially and upbraid the main character mildly when he becomes too much of a {{Jerkass}}, SociopathicHero or InsufferableGenius.

Note that if they're [[AxeCrazy actually psycho]], the arrangement usually won't work (but see the Walter Mosley novels discussed below).

Can also be defined cynically as TheDragon, but working for a DesignatedHero. Compare BigBadFriend for when the friend keeps their evil tendencies and plot under wraps. One of these in an ensemble is the TokenEvilTeammate.
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!!Examples

[[foldercontrol]]

[[folder: Anime And Manga ]]
* ''Manga/MiraiNikki'': At least in the beginning while Yukki still has his moral compass in the fully upright and locked position, Yuno Gasai is what happens when you mix this trope with {{Yandere}} and shake rapidly.
* Virid the Mad Prince from ''Manga/ThereBeyondTheBeyond'', staying true to his name.
[[/folder]]

[[folder: Comic Books ]]
* Orlando to Mina and Allan in ''LeagueOfExtraordinaryGentlemen: Century''
* {{Wolverine}} sometimes plays this role in ''Comicbook/{{X-Men}}'', in issues where the other characters are being depicted as relatively pacifistic.
* Cassidy in ''{{Preacher}}'', until we find out some of the things he did in his past...
* A ''{{JLA}}/Comicbook/{{Hitman}}'' miniseries depicted Tommy Monaghan as a PsychoSidekick for {{Superman}}, and explicitly stated the moral justification of the trope described above.
** And Natt 'The Hat' to Tommy in the regular ''Hitman'' series. Natt does things like shoot the subdued prisoner (he was only going to be sent back) and kill the innocent staff of the mafia safehouse (Tommy said 'Kill everyone'). It becomes apparent over the course of the series that Natt only (mostly) follows Tommy's creed of 'kill only bad guys' because he values their friendship.
* ''CaptainAmerica'': BuckyBarnes is portrayed this way in current books, as a creative {{Retcon}} explaining his 'harmless' sidekick persona was actually a front for shady activities a public figure like CaptainAmerica couldn't be caught doing. He makes quite a darkly hilarious contrast to the older and unfailingly idealistic [[TheCape Cap]].
* Bruce Wayne's son Damian tries to become the psycho equivalent of Robin to Franchise/{{Batman}}, to the point of trying to dispose of Tim Drake in his first appearance. [[spoiler: While Bruce was thought dead, Damian served as Robin to Dick Grayson's Batman, and Dick had his hands full trying to teach Damian proper restraint. And in the New 52 DC, Damian is Robin to Bruce.]]
-->'''Damian/Robin''': Now whose neck do I break first?
* Jailbait and Headcase to Max Damage in ''[[{{Irredeemable}} Incorruptible]]''. Jailbait was Max's sidekick/underage lover when he was a supervillain, and hasn't taken his HeelFaceTurn and JailBaitWait well at all. The last straw was when he left her behind in an attempt to ''keep her safe''. Since she's a bloodthirsty adrenaline junkie, that was the worst thing Max could do to her. Her successor Headcase is even worse -- the murder of her whole family unhinged her so badly that she's now a DeathSeeker with Max as the only anchor she has in life.
* When {{Deadpool}} and Taskmaster work together, it's usually because one is prepared to do what the other won't. Since neither of them can remember which one is supposed to be the "good guy", they trade off arbitrarily.
* [[{{Comicbook/Elektra}} Elektra Natchios]] for [[{{Comicbook/Daredevil}} Matt Murdock]]
* CIA Mercenary Eddie Fyers in the '80s GreenArrow series.
[[/folder]]

[[folder:Film]]
* Let's see now. Is this a film about [[TheMafia wiseguys]]? Is JoePesci doing his HairTriggerTemper routine? Yup? Well, there you go. To list a few examples; ''{{Casino}}'', ''{{Goodfellas}}''.
* Walter Sobchak from ''TheBigLebowski'' is The Dude's best friend and a walking BerserkButton.
[[/folder]]

[[folder:Fanfiction]]
* In the ''Literature/GoodOmens'' fanfic FanFic/TheSacredAndTheProfane, 'Zirah' (Aziriphale) is a chillingly ruthless PsychoSidekick to 'Caphriel' (Crowley), [[spoiler:who ends up having to kill him to protect Adam]].
* In ''Fanfic/TheWizardInTheShadows'' Harry comes off as this to the rest of the Fellowship. He's well aware that he's thoroughly unbalanced and that he's the Fellowship's big gun, and fortunately gets better. But for a while, he goes off like a bomb at the merest hint that someone's threatening someone he cares about.
[[/folder]]

[[folder:Literature]]
* Hawk in Robert B Parker's ''{{Spenser}}'' novels: the type specimen for the trope and one of the first to appear, resulting in a FountainOfExpies.
* Mouse in Walter Mosley's ''Easy Rawlins'' novels. A particularly extreme example in that he's ''genuinely'' AxCrazy. And played by Don Cheadle in the 1995 film adaptation of ''Devil in a Blue Dress''.
--->"If you didn't want him dead, Easy -- why did you leave him with ME?"
* Clete Purcel in JamesLeeBurke's Dave Robicheaux novels, although Dave can get a bit more morally ambiguous than is usual in such cases.
* Bob the Skull in JimButcher's TheDresdenFiles series. He's a spirit of intellect, and thus doesn't wholly understand the "morality" thing. Kincaid stands well within PsychoForHire in most cases, but acts as the Psycho Sidekick to the Archive.
** Inverted in the case of Harry and Michael. While Harry is heroic, he is more likely to do morally dubious things than Michael, who dislikes people ''swearing''.
*** Inverted a ''lot'' by Harry. He plays Psycho Sidekick to Karrin Murphy's advocacy of the law, and the White Council see him as useful psychotic that'll need to be [[ShootTheDog shot sooner or later]].
*** And on top of all of these you have [[spoiler: Ebeneezer [=McCoy=]]]. Being the PsychoSidekick to the White Council is part of his job description.
* Joe Pike in Robert Crais' ''The Monkey's Raincoat'' and the other Elvis Cole books. He actually has a moral code but is a lot more comfortable with violence than Elvis. He also has a few books centered around him.
** Mercenary Jon Stone seems to serve as a psycho sidekick to Pike.
* Mick Ballou in Lawrence Block's Matt Scudder novels.
* Hoppy Uniatz in Leslie Charteris's ''Literature/TheSaint'' novels. Simon Templar himself, on one ([[HoistByHisOwnPetard reasonably justified]]) occasion, [[KillItWithFire dealt even more mercilessly than usual with some sadistic murderers]]. The fact that Simon often has to restrain Hoppy shows just how Psycho this Sidekick really is. It doesn't help that Hoppy will do ''anything'' the Saint asks, and interprets everything through his [[WrongSideOfTheTracks unorthodox upbringing]] and [[NeighbourhoodFriendlyGangsters previous profession]]. In "The Case of the Frightened Innkeeper," Templar forgets this; meaning to tell Hoppy to remove some of the Ungodly from the Saint's presence, Simon carelessly says "Get rid of them." [[spoiler: Hoppy does.]]
* ''StephaniePlum'' series by Janet Evanovitch: Ranger, although Ranger's a bit more cerebral than most examples, and significantly less psycho than average.
* Subverted in Carol O'Connell's ''Mallory'' novels, which are about a sociopathic primary character who would usually be someone else's PsychoSidekick surrounded by sidekicks who keep her from going completely evil.
* The ''[[{{Dragaera}} Taltos]]'' books have been acknowledged as inspired by the Spenser series, but seem to turn this on its head. Vlad Taltos, the protagonist, is the PsychoSidekick in relation to his friends who are [[OurElvesAreBetter fantasy elf nobility]], but it's less that he is more bloodthirsty than that he is less bound by social conventions. This is played rather straight in ''Orca'' though as a LawfulGood police officer, who normally disdains assassins, has Vlad kill her partner who was a CorruptCop and a murderer.
* In LoisMcMasterBujold's Literature/VorkosiganSaga, Sergeant Bothari has elements of this, though Aral Vorkosigan is more active than most in acting as his MoralityChain and eventually gets him some much-needed medical intervention.
* Major Joachim Steuben in Creator/DavidDrake's ''Literature/HammersSlammers'' series is in love with Colonel Hammer -- and there's '''nothing''' so awful he wouldn't do it if he feels it'd benefit the colonel. [[spoiler: Including having himself assassinated to give Hammer the chance for a "once and for all" crackdown on the opposition.]]
--> "And sometimes a fellow who does one job well can see where his job has to be done, even though a better man has overlooked it. Anyhow, Secretary, there always was one thing you and I could agree on -- lives ''are'' cheap."
* In Creator/DavidDrake's ''Literature/{{RCN}}'' series, Adele's servant Tovera is a sociopathic killer. Mostly she stays with Adele to learn to at least mimic the behaviors of someone with a more normal mental state. Hogg is also this to Daniel Leary, being the one who does things that Leary's honor or morals prohibit.
* Lee in GordonRDickson's ''[[ChildeCycle Dorsai!]]''. Due to an uncorrectable medical condition, he's unable to tell right from wrong and is socially dysfunctional. He knows this, and seeks a ''cause'' to keep him functioning. He'll do ''anything'' for that cause. Luckily, he found Donal, who keeps Lee from doing anything nasty. Also notable that Lee likely inspired Joachim Steuben, as David Drake is a fan of the novel.
* Edward in the ''AnitaBlake'' series (although it's not like Anita's such a saint).
* Bubba Rugowski in DennisLehane's ''Literature/KenzieAndGennaroSeries''.
* ''Myron Bolitar'' series by Harlan Coben: Windsor Horne Lockwood III, or, Win.
* In ''Literature/{{Animorphs}}'' Rachel is this to the rest of the team, although they're not exactly [[KnightInShiningArmor white hats]] themselves. Reached its peak in the final two books when Jake sent her to [[spoiler: [[CainAndAbel kill his own brother]]]].
** Eventually, Rachel herself lampshades how she was made into this--the other characters kept needing someone to do bad things for the greater good, and it became easier and easier for her to be that someone. The entire team functions to enable and justify her actions.
* Willikins to Sam Vimes in Creator/TerryPratchett's ''Discworld/{{Snuff}}''.
* Morley Dotes to Garrett in the ''Literature/GarrettPI'' series.
[[/folder]]

[[folder: Live Action TV ]]
* ''Series/DoctorWho'': Leela (and K-9, a bit). While the Doctor sometimes criticises her violence ineffectually, he doesn't often intervene to stop it when it's useful. Subverted with Ace, in that a vague description of the dynamic between them would make Ace seem like a PsychoSidekick (she makes her own explosives, he does the [[TalkingYourWayOut fast-talking]] and [[TheChessmaster planning]]), but the Seventh Doctor is [[ManipulativeBastard much more ruthless than she is in a less personally violent way]].
** [[ProudWarriorRaceGuy Strax]] the Sontaran fits this role after becoming BattleButler[=/=]PluckyComicRelief to Madame Vastra and Jenny.
* Avon in ''Series/BlakesSeven'', with interesting consequences when he ended up as the central character. Unusually, Avon continues to act like a Psycho Sidekick -- but having authority this is a disaster for himself and everyone around him. It's aspects like this which make it feel like a show shot on the deck of a burning ship.
* Gene Hunt (and sometimes Ray) in ''Series/{{Life On Mars|2006}}'' and ''AshesToAshes''.
* Both Derek and Cameron in ''TheSarahConnorChronicles'' move around on the spectrum between this and PoisonousFriend in relation to the more moral Sarah and John. This occurs as early as the second episode, when Sarah holds [[spoiler: Enrique at gunpoint because she thinks he might be a snitch, but doesn't shoot. Cameron arrives on the scene by shooting him twice in the chest before anyone has a chance to stop her. Of course, she's vindicated at the end of the episode when it turns out Enrique really ''was'' an FBI informant.]]
-->'''Sarah''': What did you do?!\\
'''Cameron''': What you couldn't.
** Derek does it even more often, whereas Cameron can usually be persuaded not to kill people if John or Sarah are near. And aside from [[spoiler: the guy they thought was Sarkissian,]] all the people he kills were ''really'' close to him, namely [[spoiler: Andy Goode and Jesse.]]
--->'''Derek''': John Connor said to let you go. (''pulls out pistol'') I'm not John Connor.
* Guerrero in ''HumanTarget''. A short middle-aged man wearing round Harry Potter glasses, in the show's premiere he says the following (in a completely low-key tone of voice) to a couple of {{Mooks}} who are trying to intimidate him:
--> "I'll take the beating, because that's all you two amateurs are cleared to do. Then one night soon, I'm gonna break into your houses and kill each of you in your sleep. I'll probably start with you, Alfredo. That way Stephen here can have a few extra days with Marla and the girls. It's only fair."
** Likely also a retired PsychoForHire and a PintsizedPowerhouse. Played by JackieEarleHaley, better known as Rorschach from the ''Film/{{Watchmen}}'' film.
** [[http://www.youtube.com/watch?v=e7zvE58sAg8 Guerrero doesn't like to be interrupted.]]
* ''Series/BuffyTheVampireSlayer'': While Giles is sometimes the PoisonousFriend, the "Scoobies" are well aware of his Ripper persona. Spike is this for Dawn; at certain points in the series, she adores him despite knowing that he would be back out slaughtering innocents if not for his chip.
[[/folder]]

[[folder: Video Games ]]
* ''KnightsOfTheOldRepublic'': [[KillAllHumans HK47]] and [[ProudWarriorRaceGuy Canderous Ordo]], plus HK again, Mandalore and to [[TheAtoner some extent]] [[DarkAndTroubledPast Atton Rand]] in the sequel.
* [[BoisterousBruiser Black Whirlwind]] in ''JadeEmpire'' doesn't know of a problem that [[AxCrazy his axes]] [[WhenAllYouHaveIsAHammer won't solve]].
* Several classes in ''StarWarsTheOldRepublic'' get one, most notably [[ImAHumanitarian Khem]] [[ComedicSociopath Val]] in the Sith Inquisitor storyline.
* ''Franchise/MassEffect'': Wrex the ProudWarriorRaceGuy. The second and third games add a whole cohort of them:
** Grunt, perhaps even more so than Wrex. As Grunt's mental condition is essentially that of an adolescent who has had only minimal interaction with other members of his race, he lacks the discipline and self-control that an older, more experienced Krogan, like Wrex, has.
** Jack, by her own estimation, is a "murdering psycho bitch" when you first meet her.
** Zaeed Masanni - he's not just a nigh-unkillable badass mercenary, he's quite willing to blow up the building you're both standing in, in order to ''open the door''.
** Aria would probably kill you for considering her a sidekick, but in the Omega DLC for the third game, she'll follow your lead in combat. And while most of her unpleasantness is nigh-on clinical - rallying people to her cause in order to use them as cannon fodder - she'll choke the life out of her Cerberus opponent with her bare hands and freely admit to really enjoying it.
*** Aria's sidekick, Patriarch - "Kill the family first. Then he'll come at you stupid."
** Kai Leng is TheDragon to the Illusive man, but while TIM sincerely believes that he is only doing what is necessary, Leng appears to be in it because he likes terrorising the people he's sent to kill. [[FridgeLogic This might explain]] why so many of his targets can be saved - he's enjoying their fear too much to actually get on with the task at hand.
* The latter half of everybody's favorite crime-solving dog and rabbit duo SamAndMax. Very much so.
[[/folder]]

[[folder: Web Comics ]]
* Little Sappho, the sidekick from TheAdventuresOfGynoStar, can be extremely violent when angered, and is often willing to do morally questionable things that Gyno-Star would never consider doing.
* Baam from ''Webcomic/TowerOfGod'' is a decent, idealistic fellow. His best friend [[MagnificentBastard Koon]] however he describes aptly as a Devil.
* In ''WebComic/BasicInstructions'' the Knifeketeer (who isn't exactly Mr. Boy Scout himself..) [[http://basicinstructions.net/basic-instructions/2011/1/13/how-to-handle-exposition.html has Stabby]], who more than lives up to his name.
[[/folder]]
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