-->''[[WellIntentionedExtremist The road to Hell is paved with good intentions.]]''
-->-- '''Old proverb'''

-->'''Mitani:''' ''I mean, really, when you think about it logically, what's so wrong with being gay? And as long as you're gay, what's wrong with taking a student lover half your age? And seeing your young lover mutilate himself horribly? And poisoning a priest when he finds out what you've been up to? And then horribly mutilating another young lover when he finds out about the first one?''
-->'''Tsuzuki:''' ''...I guess this would be that 'slippery slope' argument I keep hearing about.''
-->--'''Cropped Scan Theater'''

The heroes encounter someone who engages in behavior that is an [[GrayAndGreyMorality uncomfortable shade of gray]]. Someone who is just killing off enemies/criminals, or fighting an ally-of-convenience of the good guys.

There is an implication that what that "someone" is willing to do makes the good guys look negligent and a little under-committed to the cause of good.

Thankfully, before the heroes have to [[ALighterShadeOfGray question their own morality too much]], said gray suddenly turns black. The "gray" start engaging in obvious "too far" behavior, usually with a touch of fanaticism, becoming {{Well Intentioned Extremist}}s. [[DebateAndSwitch The good guys no longer have to ponder the ramifications of the original behavior]]. [[StatusQuoIsGod Status quo is restored]].

The {{Aesop}} here is supposed to be the [[http://en.wikipedia.org/wiki/Slippery_slope Slippery Slope Argument]], but it is fast-forwarded due to time constraints.

This is the opposite of a series recognizing that some people have to ShootTheDog, a lucky character may realize they've [[KickTheWrongDog Kicked The Wrong Dog]].

Compare with ContrivedCoincidence, MoralEventHorizon, and MotiveDecay.

Sometimes this happens with the protagonist, leading to MoralDissonance or [[WhatTheHellHero What The Hell, Hero?]]

----
!!Examples:

[[foldercontrol]]

[[folder:Anime & Manga]]
* Masterfully avoided in Higurashi. [[spoiler: Shion goes insane and embarks on an attempt at revenge after the boy she loves, Satoshi, disappears. Alot of people are captured, killed or both, including her twin sister, her sadistic grandmother, and the village headman, who are all part of the village mafia. Then Shion goes after Satoshi's little sister, Satoko, because she's mad that Satoko's dependence on Satoshi wore him out. Shion captures Satoko and tortures her to death. ''Then she remembers that Satoshi's last request was that she care for Satoko for him.'' Shion was already crazy, but now she loses any pretense of acting for anything besides her own dark pleasure.]]
* ''{{Death Note}}'': Yagami Light begins using the supernatural notebook to rid society of criminals, but soon his black list expands to include anyone who stands in his way for any reason, starting with the FBI. Along the way, he coolly manipulates the feelings of both people and shinigami. Repeatedly stating that he plans to become the god of the new world he is trying to create doesn't help matters, either.
** For that matter, Mikami Teru uses the notebook to eliminate minor and reformed criminals.
** Declaring that he will eventually execute people for being lazy implies that Light has done away with the slippery slope completely and simply jumped off the metaphorical deep end.
** And, of course, Mello joined the Mafia and killed and threatened innocents for the sole purpose of tracking down Kira.
* Recently DoubleSubverted in ''{{Naruto}}'' [[spoiler:Sasuke went from betraying his village to kill Itachi for killing his clan to wanting to destroy ''the entire village'' because some (but not all) of the higher ups of it convince him to do it (even though his clan was planning to start ''a civil war''). However, he then told his teammates that he was only really gunning for the top brass and only siding with Konoha's enemies for now. But ''then'', he tells Madara that he wants to destroy it and every man, women, and child in it.]] Of course, all of this just throws his goals even further into the air.
** While Danzo [[StrawManHasAPoint does make a point about the state of affairs in Konoha and the ninja world in general]] it's slowly becoming clear that he doesn't care about what he needs to do to achieve those goals.
* In ''CodeGeass'', Lelouch Lamperouge wanted to destroy the Empire of Britannia (despite being an ex-Imperial Prince) and started to organize LaResistance. However, as time passes, he becomes more hardened and crazy, going as far as [[spoiler: massacring children and unarmed people for possessing Geass powers and being a part of a Britannian-sponsored cult... which ''trained'' the children in it to use ''their'' Geass to make a guy murder his own allies. Let us not forget Rolo, THE TykeBomb of the series, was raised there too.]]
** To be fair to Lelouch, it is hard to see a way to justify [[spoiler: letting those kids live. With those sorts of gifts, almost instinctual use of violence to solve problems, and lack of human contact, they'd be destined to become more Maos and Rolos; that is, not actually dangerous to the world as a whole like Lelouch or the Emperor, but plenty dangerous to society at large. Could a whole generation of Geass-using sociopaths prowling the streets possibly be a good thing?]]
*** However, beyond just the [[spoiler: Geass-wielding children, there were also scientists present at the laboratory, who were also killed. He ordered everyone to be slaughtered. Also, it should not be forgotten that Lelouch originally intended to control the Geass Cult to become more powerful than TheEmperor.]]
*** [[spoiler:He did originally decide to control the Geass Cult, but that was before Rolo murdered Shirley, which made Lelouch realize that Geass was too much of a liability. (As if he didn't already realize that when it came to Mao and his father.) Though yes, even though he was in the middle of a RoaringRampageOfRevenge, he should have spared the lives of the scientists. Though this troper has also heard an argument that even they could have secretly possessed Geass as well, which given the nature of Geass is entirely possible.]]
*** [[spoiler:You mean the scientists using kids as test subjects and forcing them to kill? Yeah, he really should have spared them...]]
** Then there's Suzaku who finally decide to have end justify means and drug Kallen to get a confession out of her. [[spoiler: Unlike Lelouch, he doesn't go through it.]]
*** That reservation goes away [[spoiler: as soon as he nukes Tokyo]], at which point all his old sensibilities die on the spot and he embraces Lelouch's ideals. YourMileageMayVary on that being CharacterDevelopment or CharacterDerailment.
*** Of course, he was making his way down the slope well before that. Whereas in season one he was more of an ineffectual idealist, he jumps the slope the minute he turns Lelouch in to TheEmperor in exchange for a promotion to Knight of Rounds, an act of utter betrayal in spite of the apparent circumstances, in the process effectively becoming an enabler of Britannia's policies, even though he still believes he can change things from within. In reality though, he only cares about helping Japan. (Other than this, he's helping conquer EU states in hopes of currying favor points with the Emperor that he might become Knight of One.) Hence, he's already using the ends to justify the means. Then again, let it never be said that Suzaku isn't hopelessly in denial throughout most of the series. At least the above bullet point knocked some sense into him.
** And of course, we have TheEmperor and V.V, [[spoiler: who after suffering immense loss as children, do the exact same thing fifty years later, even though they said they will eliminate lies. Not to mention V.V. is to blame for ordering the brainwashing and training of Rolo and the kids...]]
** In general, ''everyone'' in Geass flew off slippery slopes.
*** Lelouch and Suzaku are the extreme cases. As well as the others named above. Ironically, [[spoiler: Euphemia, who actually goes on a rampage, killing Japanese people, only did so because she was under the power of Geass and had no choice.]]
*** There's also Nina. The spoiler above is enough reason for her to [[spoiler:want all of Japan to die in retaliation]]. She at least sees the error of her ways eventually.
* In MobileSuitGundam00, the Trinity group shows up and starts actually destroying military bases and arms manufacturers. Most of the battles up until this point had hundreds of civilian casualties, with one battle threatening to basically screw the entire world with nuclear radiation. Through destroying military installations instead of waiting for war to start, Trinity is preventing these needless deaths. However, the "it's not right to attack before you're attacked" excuse is played, Trinity is painted as villainous when it's actually clearly good... and it suddenly starts blowing up random buildings for no reason. Let's also point out that the villains out to cause perpetual war for personal profit are never portrayed in nearly such a negative light.
** While Trinty's actions may have been jumping of the slippery slope they were hardly 'clearly good' in the first place- Gundam 00 is full of GreyAndGrayMorality and the point is that no one side is clearly good or clearly evil. The Trinity's actions were simply causing more needless deaths by murdering civilians in arms factories and blowing up military bases which weren't attacking anyone, simply defending their homeland. Trinity's actions are a classic example of jumping of the slippery slope by quickly resorting to overly extreme methods, and are hardly unambiguously good ones being wrongly portrayed as evil. And forgive me if I'm wrong but I can't remember anyone in the series who wanted perpetual war, well besides [[CompleteMonster Ali Al-Saachez]]
** Depending on your viewpoint, Celestial Being itself was doing a lesser version of this before Trinity even showed up. They certainly had no compunctions about blowing up a training facility for SuperSoldier children, and all the civilians inside, as a revenge operation.
[[/folder]]

[[folder:Comic Books]]
* The majority of heroes who meet ThePunisher in the MarvelUniverse are usually [[TechnicalPacifist Technical Pacifists]], so most of them think that this AntiHero has jumped off and is now gaily frolicking at the bottom. In fact, any AntiHero who lives in a [[TheVerse verse]] that's on the idealistic side of the SlidingScaleOfIdealismVersusCynicism could be said to have jumped, at least from an in-universe perspective.
** Averted sometimes in the MarvelUniverse when he ''doesn't'' kill (for various reasons, mainly when having to team with the majority of the protagonists), and averted in his MAX series where to date things have been almost entirely on the cynical side and... Then again, arguably he's not treated ''that'' nicely there either, it's just that his targets are apparently much, ''much'' worse, and the reason that he keeps a select few alive? [[ToThePain Well]]...
*** Garth Ennis admitted that [[AuthorTract his sheer anger regarding human trafficking and sex slavery led]] to the infamous arc "The Slavers," which has Frank Castle [[spoiler:graphically disembowel a slaver, throw his sister face first into a window repeatedly until the shatterproof window breaks off from the frame, and then set their father on fire]]... even after Frank admits that this won't make a big difference and that he's just going after their group, and at the end his inability to really help the victims.
* IronMan started the MarvelComics ''Comicbook/CivilWar'' CrisisCrossover with a perfectly valid idea: that superheroes should be held legally accountable for their actions, and should all register their identities with the government to help enforce that. Then they started conscripting registered heroes, arresting everyone with powers who didn't register (whether they intended to use them or not), restraining former friends in secret prisons, ''turning loose mass-murdering supervillains'' so they can work as government-sanctioned enforcement agents (barely held in check by nanites, and that didn't last long), '''cloning a [[PhysicalGod god]]''', etc. etc., turning supporters of registration into {{strawman political}}s. (Tony's fans complain that he didn't jump, he was pushed by the writers.)
** The Clusterfutz is made only more mindbending when Mark Millar, the man who wrote most of the mainline story, is basically on the record that, at least in the main book, the people we were supposed to agree with were the ''Pro-registration'' people. Even after countless upon countless WhatTheHellHero moments. And Sally Floyd....[[WallBanger Oh, Sally Floyd...]]
* Often happens in ''Comicbook/{{X-Men}}'' comics, with debates about the rights and wrongs of mutant cures being short-circuited by revealing the cure is poisonous, or was created by illegal experiments on mutants, or something similar.
** Went back-and-forth in [[JossWhedon Whedon's]] Astonishing run. The cure is a threat to mutants - but so many mutants want it - but it was developed in a horrific way - but it was all done because an alien was trying to save his civilisation - but that civilisation was horrible - but what about the children?
*** The children have [[TheSimpsons potassium benzoate.]]
* [[GreenLantern Hal Jordan]] got so pissed off than the Guardians forbid him to use his ring to temporary recreate Coast City that he flew to Oa, maiming numerous other Green Lanterns in the way and stealing their rings (how did they survive the vacuum of space is unknown), killed Kilowog, killed Sinestro, absorbed the whole power of the main battery (destroying it in the process), became the villain Parallax and then tried to destroy the universe in order to recreate it "the right way". Of course, it was later retconned as he being [[DemonicPossession possessed by the fear entity Parallax]], but still...
[[/folder]]

[[folder:Film]]
* Anakin in ''StarWars''. Specifically, note how quickly he goes from [[spoiler: agonizing over his role in Mace Windu's death]] to [[spoiler: killing children being raised by the Jedi without a problem]].
** Also, in the EU, Jacen Solo's means to an end actually make sense, even after [[spoiler: he becomes a Sith]]. However, you realize a few books before the finale that he's completely lost touch with his original philosophy and is just retroactively trying to justify his insane actions.
* The character of [[spoiler:Amanda]] in the ''{{Saw}}'' movie series makes Jigsaw look downright merciful by the third movie.
* ''MagnumForce'' has Dirty Harry dealing with cops who have been executing guilty criminals who escaped justice due to technicalities. When he refuses an offer to join them, they try to murder Harry, thus proving they didn't have a complex or unorthodox sense of justice after all, they just like killing. Just once this troper would like to see this theme revisited in a film or TV show where the criminal-executing folks actually just end up facing the music for their actions, because it turns out they really are idealistic and refuse to murder innocents or people who get in their way.
** {{Dexter}} comes close. But this troper finds Yagami Light a lot more realistic.
* ''CrimsonTide'' is often noted as quite admirably morally complex for a Jerry Bruckheimer film, with Gene Hackman's character given quite a bit of sympathy in wanting to launch the missiles. At least until the ending, when he makes a thinly veiled racist comment to Denzel Washington, which Washington promptly reverses on him.
** There's also the fact that Gene Hackman's character gets increasingly loud as the movie continues, yelling and screaming at people, while Denzel remains calm and logical, which serves to show you just who's right.
* ''TheDarkKnight'', [[spoiler:Harvey Dent]] wasn't so much "jumping off" as much as [[spoiler:the Joker [[HannibalLecture kicked him]] off it]].
* SweeneyTodd goes from wanting to just get [[RoaringRampageOfRevenge revenge on two specific people]] to [[SerialKiller randomly murdering]] people off the streets who won't be missed and having them ''[[ImAHumanitarian baked into pies]]'' about halfway through the movie. (Same thing goes for the stage version as well.)
[[/folder]]

[[folder:Literature]]
* In Damon Knight's short story ''The Analogues'', a scientist invents a procedure to create a "better conscience" in the form of hallucinations that prevent you from committing crimes. This raises a lot of questions about the morality of removing free choice, but then it turns out the scientist plans to use it to take over the world, and has [[spoiler:already used it on the protagonist to prevent him from stopping the plot]].
* {{Eragon}} went from wanting revenge to strangling unarmed guards and killing left and right.
* King Erius in [[{{Nightrunner}} Lynn Flewelling's]] ''Tamir'' trilogy starts by taking the throne from his insane mother, who was executing people left and right, in defiance of the divine edict that for no apparent reason essentially promises Bad Things if a man ever rules the country. Bad Things happen. He then proceeds to institute sexist practices and start killing off his female relatives...
* After what seems like half the book of everyone warning Eisonhorn not to 'cross the line', what does he do? [[spoiler: Keep the Malus Codicium and resummon the demon he just banished, out of what seems to be pure spite.]]
[[/folder]]

[[folder:Live Action TV]]
* ''StarTrek'' had numerous cases of this. For example, in ''StarTrekVoyager'' a race of holograms rebel against a race that had been hunting them, and start freeing all other holograms in the area. Even Voyager's holographic doctor joins them. But then they start killing off anyone who ''might'' enslave an intelligent hologram.
** Then they move onto anyone who uses humanoid holograms at all, regardless as to whether those holograms are intelligent.
* ''XenaWarriorPrincess'' had Najara, a character who either converted or killed criminals. Rather quickly, Najara is revealed to be insane, and can't tell the difference between obvious criminals and lesser offenders.
* ''{{Supernatural}}'' had an episode where the Winchester brothers met a rogue vampire hunter. Despite seeming like a decent enough chap and a worthy ally, the more experienced hunters tell the boys the guy is bad news. The new character makes a swandive off the slope when the local vampires turn out to actually be peaceful and swear not to kill humans, yet he still attempts to slaughter them - then goes out of his way to attack the protagonists for protecting the vampires.
** I also thought the Winchester brothers were pretty stupid for being so ready to believe what the vampires told them. Don't vampires ever lie?
* ''BuffyTheVampireSlayer'': Soon after Faith's arrival, the enjoyment she gets from slaying begins to make Buffy question the job. But just as Buffy is coming round to Faith's way of thinking, she does something that cements her position at the bottom of the slope, and Buffy's dilemma is over... although she still agonizes about it, until Faith makes a point of attacking Buffy's [[{{Nakama}} circle of friends]] directly.
** Another example occurs in the season 2 episode "Phases". A werewolf hunter shows up and at first there appears to be a moral dilemma over whether it is morally acceptable to kill werewolves (who kill people, but aren't in control of their actions). Fortunately, the hunter quickly reveals himself to be evil, and so an exploration of whether it is moral to [[IncrediblyLamePun shoot the dog]] is avoided.
* ''BattlestarGalactica'': The "Pegasus" arc has been accused of this by some critics, with Admiral Cain taking about twenty minutes to go from merely being a hardassed martinet to ordering the rape of a pregnant woman as a JackBauerInterrogationTechnique and sentencing the crewmen who interfered to summary execution. In fact, the episode "Pegasus" had had to be radically trimmed to fit network time constraints; some of the footage that was lost (and reinstated on the DVD) implied the passing of more time than seems to go by in the episode as aired. The ''Razor'' movie, which came later, gave Cain a PsychoLesbian backstory to explain her excesses.
** The betrayal of Gina didn't explain her excesses, she shot her XO in cold blood for disobeying orders in battle before she learned her lover was a Cylon. She was just that hard, which also allowed her to quite impersonally order the torture and interrogation of said Cylon. If there's a FreudianExcuse in "Razor", it's probably that she failed as a child to protect her little sister because she was too scared.
** There's also the episode where the woman put in charge of a tribunal takes about 24 hours to go completely nuts with power, and attempt to accuse the commanding officer who appointed her of the crime she's investigating.
** Similarly, in the 'Black Market' episode, the leader of the organisation running it does a pretty good job of defending the need for a BlackMarket in the fleet. Then he talks about having child prostitutes, so [[spoiler: Lee can shoot him without feeling guilty]]
*** Lee did acknowledge the argument about the need for a black market, though, given that he allows it to stay in business afterwards. He just wanted them to clearly understand where the [[MoralEventHorizon limits]] were.
* Seems to happen about once a season in ''DoctorWho''. A few notable examples;
** "The Mind of Evil"; a scientist invents a machine that removes criminal impulses from the human mind, and offers it to the government as a means of dealing with dangerous criminals without resorting to the death penalty. Turns out its inventor is actually the Master and the device brainwashes people to serve him.
** "Genesis of the Daleks"; Davros invents the Dalek (or "Mark III Travel Machine, as he initially calls it) ostensibly for the purpose of making life easier for mutated Kaleds. When his superiors start getting cold feet about the research, he has the entire Kaled race wiped out.
** "Rise of the Cybermen"; When the British government refuses to fund John Lumic's Cyberman research, he kills the leadership and begins forcibly cyber-converting the British population.
** Not forgetting the Doctor himself in "Boom Town", where the Doctor is placed in a tricky moral quandry about turning over a surrendered, helpless enemy to the alien's authorities, who will execute her. Thankfully the alien then tried to blow up Cardiff so she could escape Earth on a space surfboard, establishing that she was a bitch all along.
* Holly in ''SlingsAndArrows'' wants to streamline the Festival's business end and replace most of its {{Shakespeare}} with musicals. This is only marks her as a villain in the context of a show where Shakespeare is SeriousBusiness, until she starts abusing her boyfriend and deliberately aggravating the heart problem of a board member who disagrees with her.
* Gerak in season 9 of ''{{Stargate SG 1}}''. At least he got a [[RedemptionEqualsDeath redemptive death]], though.
** The Ori could stray into this. At first it seems that, while their practices are primitive, their ultimate goals are noble enough, helping others to acheive ascension. Then it's revealed that this is all a lie, and the Ori are manipulating people's belief to gain more power.
*** The rogue NID. At first they're stealing alien technology with the purpose of using it to defend earth, making them into [[KnightTemplar Knight Templars]]. Then it turns out they're just in it for the money.
* Similar to the ''MagnumForce'' example, season two of ''MurderOne'' featured a storyline about Clifford Banks, a serial killer who tracked down and executed criminals who escaped justice, or had an unsuitably short prison sentence. He started out on this path through the murder of his retarded brother, he never kills innocent people, and throughout the arc a few people comment that "sometimes the streets need sweeping." Any moral ambiguity is then done away with by the lawyers finding out that Clifford actually killed his brother himself over his frustration about giving up his whole life to care for him, causing a mental breakdown that directed his guilt outwards onto other criminals.
* In the pilot episode of ''{{The Shield}}'', Vic Mackey partakes in numerous criminal acts including the use of excessive force during arrests, working with a drug dealer and beating a suspect with a phone book in order to make him talk. Then, at the end of the episode, he [[spoiler:shoots another police officer in the face to prevent him from gathering evidence against Vic's team]].
[[/folder]]

[[folder:Tabletop RPG]]
* ''[[WorldOfDarkness Vampire The Masquerade]]'' has an actual mechanic for this: acting like an inhuman, unprincipled bastard will make you more of an inhuman, unprincipled bastard.
** This applies to all World of Darkness games and is a large part of the new system.
* Chaos in ''{{Warhammer 40000}}'' is grease on the Slippery Slope. As Chaos is a sentient form of TheDarkSide by way of TheCorruption, this trope becomes rather understandable.
[[/folder]]

[[folder:Video Games]]
* In ''{{Bioshock}}'', [[spoiler:harvesting more than two of the Little Sisters gives you the bad ending; it is simply implied that you jumped off the slope and became ADAM and power-hungry the moment you first harvested]].
** This is actually [[JustifiedTrope Justified]]--[[spoiler:killing the Little Sisters gives you more ADAM, and why should you be immune to the {{Psycho Serum}} that's turned the rest of the city into twisted freaks?]]
* Subverted in ''Rondo of Swords''. After a very harsh FriendOrIdolDecision that ends up on the favor of the Idol, Serdic experiences an immediate Karmic backlash, complete with [[DarkMessiah title change]], [[DiscardAndDraw power swap]], and [[EvilMakeover costume switch]] to reflect his [[ShootTheDog dog shooting]]. While his Nakama repeatedly [[WhatTheHellHero accuse or suspect him of jumping off the slope]], Serdic experiences no lapse in emotional or moral health. The epilogue also reveals that he was a just and well-loved ruler with a happy marriage.
* CJ and Niko from ''GTA San Andreas'' and IV, respectively. Let's assume that they're good-hearted people at the start (if the cut-scenes are any indication), and let's assume the player doesn't do any killing not encouraged by the storyline (which is a stretch, but go with it). Now watch how their lives unfold. CJ in particular goes from "I guess I'll kill this guy since he's been screwing with my gang" to "guess I'll just kill all these guys for no apparent reason" so quickly it might make you wonder if you're still playing as the same guy.
** CJ's transformation ''is'' surprisingly gradual for a GTA game, actually. At first he's trying to protect his family and friends. Then he's manipulated into killing people, where if he doesn't, either he or his family will get killed. As the game continues, he eventually decides to kill the people who manipulated him. If you play a PacifistRun (damn near impossible, but let's assume), then the only people CJ will kill are people that are threatening him, or people that he's threatened into killing.
*** [[DisproportionateRetribution And some people who were rude to his sister.]]
** Well, Niko may seem pretty nice at the beginning of the game, but the plot [[spoiler:eventually reveals that he is a war criminal out to kill other war criminals.]] So there's a good argument that he starts the game as a major bad guy, and indeed commited even more horrible acts before the game started than you can ever do in it.
* ''MegaManX 8'' has [[spoiler:Lumine, a New Generation Reploid, and director of the Orbital Elevator project. ''He's the '''BigBad''''', '''not''' Sigma this time]].
** It doesn't help that the whole of [[spoiler: Lumine]]'s tale plays on the game's subtitle, ''Paradise Lost''. [[spoiler: Lumine is the analogue to Satan, rising against his creators and their vassals. He even seems to have enough truth in his words to shake up X into being completely unable to attack.]]
* Malygos from ''WorldOfWarcraft'' goes from a dragon who wants to rein in mortal spellcasters because he disapproves of their methods to a dangerously extreme tyrant who seems genuinely unaware that his plan to redirect and control magic has an excellent chance of ''destroying Azeroth''.
** Kael'thas Sunstrider's goal was originally to improve his suffering people. However, thanks to a combination of [[EvilIsNotAToy Fel magic taint]] and his own lust for power, he goes insane and becomes a zealously loyal servant of Kil'Jaeden.
** Illidan was always a self-serving JerkAss, but he had a more gentle side to him. After nearly being killed by Arthas, though, that gentle side was replaced with paranoia, insanity and a desire to crush anyone he deems as a threat, which happens to be ''everyone not on his side.''
** The Scarlet Crusade (at least those within the Monastery) can be accused of this.
**And, while we're on Warcraft games, as you play the human campagn of Warcraft III, Arthas starts out as a Dedicated deciple of Uthar Lightbringer (even though arthas is a Prince, Uthar's millitary rank is higher than Arthas's, and they both respect that) but gradually starts betrayiong more and more people, and becomes less and less concerned with the whole reason he's fighting the Undead in the first place. Eventually, [[spoiler: he totally betrays Azaroth, dresses in Undead armour, and kills his own father. In fact, in World of Warcraft, the very throneroom in which he killed his father is now directly above Undercity, the Capitol City of the Undead.]]
* In ''Mitadake High'' it is common for someone to RP themselves going insane as a result of the madness going on around them. Unfortunately, not everyone is any good at it.
* In ''FireEmblem: Path of Radiance'', the country of Crimea is good with bits of gray, Daein is dark gray but with evil leaders, and conservative Begnion was in the middle with its corrupt Senate but well-intentioned leaders. When the sequel rolled around and Begnion would be the main antagonist, well you bet that country started being ruthless.
[[/folder]]

[[folder:Webcomics]]
* In ''TheOrderOfTheStick'' paladin Miko Miyazaki starts out as a narrow-minded, HolierThanThou KnightTemplar who the titular Order despise and even her own comrades tend to look for excuses to send her off on missions to distant lands that keep her out of town for long periods. Then she [[spoiler:overhears Lord Shojo talking to Roy and Belkar about their plans to do the dirty work behind the paladins' backs, ignores his [[IDidWhatIHadToDo perfectly good arguments about why he had to do it,]] declares him guilty of treason and executes him on the spot. She's IMMEDIATELY stripped of her powers by the gods for murdering an unarmed octogenarian and goes into a psychotic breakdown when she refuses to accept that she could have been wrong.]]
** [[spoiler:Vaarsuvius]] just took a jump, too. See comic [[http://www.giantitp.com/comics/oots0639.html #639]]. Though debates on whether this counts as PayEvilUntoEvil, and whether that stops it being this trope, rage on the forums endlessly.
[[/folder]]

[[folder:Western Animation]]
* The ''BatmanTheAnimatedSeries'' episode "Lock-Up" introduced Lyle Bolton, ruthless head of security at Arkham Asylum, who eventually goes crazy and becomes the supervillain Lock-Up. He starts off making some good points about his regime bringing Arkham's role as a CardboardPrison to a halt. Fortunately - so to speak - he also turns out to be a sadistic monster who steps way past his boundaries and abuses his inmates, allowing Batman to take him down without any worries.
** When new-vigilante-in-town The Judge shows up later on, attacking the villains and not caring whether or not he kills them, this is never even brought up; it is taken for granted that his actions are wrong. (The big jump probably comes moments before Batman intervenes, when he is about to kill a small-time corrupt politician, but still.)
* Also, in JusticeLeague, Cadmus. Their stated goals: Provide America (and her allies, probably) a defense against the super powered types, especially the Justice League. What with Superman nearly taking over the world when being brainwashed by Darkseid, the Justice Lords in a parallel universe taking everything over, and the Justice League having a freaking Orbital Superweapon pointing down, this seems entirely okay. Up until the cloning, torture, firing nuclear weapons, being allied with Luthor, creating Doomsday...
** For this troper, what made Cadmus utterly irredeemable wasn't the allying with Luthor, creating Doomsday, the cloning or the firing nuclear weapons. It was finding out that [[spoiler:they were responsible for putting Ace (the youngest member of the Royal Flush Gang) through hell, robbing her of having a halfway normal life and, eventually, killing her via overloading her brain by pushing it to the point where she got far too powerful to be able to handle it.]]
** And the Justice Lords from a parallel Earth. Superman abandoning ThouShaltNotKill to stop Luthor from starting a nuclear war: justifiable. The entire team doing away with the concept of JokerImmunity altogether and resorting to killing and lobotomy on a semi-frequent basis: arguable. Setting up a totalitarian state in which elections do not happen until the Justice Lords say they do and people can be arrested for complaining too loudly: seems unnecessary.
* AvatarTheLastAirbender gives us Jet, whose goal it is to protect children like himself orphaned by the war mongering Fire Nation and to fight back. However, its made pretty clear that Jet has jumped off this slope when he attempts to [[spoiler: drown an entire town uninvolved with the war effort, murder innocent elderly people, and put his own life at risk for the purpose of revenge]]. He notably later attempts to jump back ''on'' the slope, but it [[RedemptionEqualsDeath doesn't turn out too well]].
** It's implied he had already fallen that far long before they met him- the plan was already in place and he had apparently been attacking travelers indiscriminate to their threat-level for a while now. Not to mention his "enforcers" thought nothing of Jet ordering them to kill Sokka. It's not entirely clear whether he truly regretted his actions for being ''morally wrong''.
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