This is Marie D'Artois' schtick in Anno1404 - she will destroy anyone who go against what she believes is right and holy, civilian or not. During the story mode, she even leads an army that could effectively be seen as an analogue to the real life organization.
Silver starts off as one of these, and is corrected when Shadow administers a good thrashing, followed by his famous kick to the head. This truly is the best way to make a Knight Templar see sense.
The Sarafan Brotherhood of Legacy of Kain are depicted as fanatical hunters of vampires and other such non-humans who embark on relentless genocides of them simply for being different, all while deluding themselves that their crusade is noble and righteous. During the final boss of the first Soul Reaver, Kain explicitly tells Raziel that the Sarafan were not noble or altruistic, and in fact sought to take over Nosgoth just as he did.
Moebius's mercenary army also qualifies; after seeing the corpses of their victims in Soul Reaver 2, Raziel quickly declares Moebius' "humble crusade" as nothing but ruthless persecution.
That seems to be the goal of the modern Templars. When you talk to Dr. Vidic in 2012, he mentions how both 12th century Earth and modern earth are the same, with society being unorganized and corrupt, and that the goal of the project he is putting Desmond through is to bring a sense of order to the world.
The sequel reveals that a large amount of the disorder and corruption in society comes directly from the Knights Templar to begin with. As they see themselves as the only sane and reasonable organization, eliminating individuals who are truly good and powerful, and who coincidentally interfere with their personal agendas, is entirely reasonable. To give an idea just how twisted their view is, Hitler was a member, as was Stalin, Franklin Roosevelt, and Winston Churchill. It strongly suggests, however, that a good bit of the Templars in late-1400s Italy were actually "in it" for personal gain, or otherwise using the Templar Order's ideals as political cover to be personally scummy, i.e. Marco Barbarigo. Cesare Borgia, the main antagonist of Brotherhood, doesn't even bother with that pretense and is all about military conquest and personal glory/greed, not even mentioning the Order. The Templars in "Revelations" seem to go back to the roots of what they intended. Prince Ahmet believed that Utopia Justifies the Means as it would create a world where nobody is divided by their differences.
In extra material, it is shown that the modern Templars view the Borgia Family's leadership as a black mark and one of the most disgraceful periods of their organization's history, due to family's abandoning of the Templars well-intentioned motivations and goals, striving more to gain power for power's sake than for the world's sake.
Assassin's Creed: Rogue portrays the Assassins as Not So Different from the Templars. They're so rigid and fanatical that they order the protagonist's death rather than consider the possibility that their playing around with First Civilization artifacts may have led to the deaths of civilians, they consider the murders of defenseless old men to be great victories for their cause simply because they happened to be Templars, and their membership is so conditioned to blindly follow orders that they instantly turn on one of their own at a word from the leadership, without even asking what he did to merit death.
In Baldur's Gate 2, Jaheira's personal quest revolves around a radical branch of the Harpers who believe that you must die due to your nature as a Bhaalspawn, regardless of whether you're a heroic person or not.
Sofia Lamb, leader of a sinister cult in the ruined undersea dystopia of Rapture during the events of BioShock 2, is this. She believes that utopia cannot precede the utopian, plans on making humanity devoid of free will and self-awareness, and thinks that every action must be for the "Greater Good". She doesn't care about any moral arguments, individual pain, or suffering caused by her philosophy (kidnapping girls from the surface to make more Little Sisters to keep a bunch of insane mutated folk living in an abandoned underwater dystopia with a large supply of mutagenic drugs, because, in her mind, the pleasure gained by the Splicers overrules the suffering to the girls' families, is perfectly acceptable), and plans on injecting her daughter with all the minds of Rapture, making her into a mindless...thing that only serves the "common good" as defined by Sofia. It's even worse than it sounds.
City of Heroes tries to portray the Malta group as this. In practice, there's little, if any, difference between what they do out of ruthlessness and what the other villains do out of greed.
Nemesis is another example, and one that never really pretended to be good in the first place. He's always been after the fascist control of the world, and just picked up the method of taking over or blocking dangerous heroes and villains while providing safety after the previous method of killing civilians didn't work.
The Countess Crey is somewhat of a Knight Templar. Originally a girl named Julianne Thompson, she started out by trying to form a team of metahumans to make the world a better place. When she was denied this due to a criminal history, she murdered a woman, took her identity, used her wealth to marry Count Crey, and then put him into a coma so that she could act out her plan. Most of Crey's work is well intentioned, but her methods are downright evil...
Longbow's dogged pursuit of justice is so single minded that, in one arc, they attempt to arrest every member of Vanguard over a few rogue operatives. Vanguard has long been controversial due to it's policy of accepting both Heroes and Villains as members, but the general consensus is that arresting every member would be a very bad idea. What makes it even more ridiculous is that Vanguard is a branch of the UN, and Longbow's just a private company.
Scirocco is also a textbook example, planning to use magic in order to force good on every villain in the world.
Issue 19 added special missions in which player characters about to make a Face–Heel Turn are depicted this way. In one instance you attempt to teach a Longbow officer that you have to kill, rather than just arrest, evildoers in order to discourage their comrades. When the officer sticks to his principles you end up fighting and killing him. Whoa.
A custom group in two Mission Architect stories, the Shields of Fiminster, believes certain creatures such as vampires to be fundamentally evil, even if they obviously have free will and fight alongside other heroes – the Shields will just suspect the latter of corruption. This makes them the main antagonists in Crusaders vs. Heroes, in which they were going to join forces with the Legacy Chain to fight the Rogue Isles Villains, but one of the Villains exploits their beliefs to trick them into fighting the Paragon Heroes instead.
Both the Brotherhood of Nod and the Global Defense Initiative of Command & Conquer can be considered Knights Templar, especially in the later games, where the more "good guy" traits of GDI start getting subsumed in their aggressive ruthlessness after Nod attacks them.
At the end of of Dm C Devil May Cry, Vergil has revealed himself to be one. At the last mission of the game, when Dante, Kat and he are looking at the city as Limbo has fallen upon Earth, Vergil responds "The path is clear for us to rule". A thoroughly confused Dante and Kat question this and Vergil's reply is that humanity has failed in its endeavors to self-govern and they must be guided by someone, that being Nephilim. Dante, believing that accepting Vergil's outcome would only be replacing one evil ruling class with another, fights his brother. He gets worse in the Vergil's Downfall DLC, to the point he straight-up drops any pretenses and succumbs to his lust for power.
The Chantry templars of Dragon Age are interesting studies of this behavior. While they do hunt down bad mages, many of them have a hard time differentiating a bad mage from a perfectly good one, and are all too willing to completely purge the Mage's Circle if anything goes wrong. This has happened at least once per century for the last seven hundred years. According to the Codex, candidates for the order are chosen first and foremost for religious conviction and martial aptitude. They're administered lyrium in order to assist them in fighting evil mages - but a conversation with Alistair implies that the entire purpose of the lyrium is to get them addicted, ensuring their loyalty. They track and destroy dangerous rogue mages - but a conversation with Wynne implies that many mage-hunters take a sadistic pleasure in their work, and two sidequests can result in the Chantry considering an Exalted March against the dwarven city of Orzammar.
What makes the Chantry even more interesting is that this is subverted just as often as it is played straight. While there are definitely those templars who are extreme in their methods, the Warden meets quite a few who are more reasonable and J,. They are partially justified because what they guard against — demonic possession from the Fade — is real, subtle, and very, very dangerous.
The Grey Wardens themselves also offer an interesting variation on this, both subverting this and playing it very straight. The Wardens are single-mindedly determined to defeat the Blights whenever they arise, whilst remaining vigilant in the shadows when they are not. What makes the Wardens an interesting variation when subverting this is that they remain politically neutral in all internal affairs, often serving in a diplomatic capacity between nations and factions, while accepting members of all races and nations in Thedas without a thought. In this capacity, the Wardens can be seen as an order of Warrior Monks who maintain and attempt to keep the peace in Thedas. However, when the Blights and the Darkspawn emerge once more, all bets are suddenly off in what the Wardens will do, which, as we're often reminded in the game, can lead to, as Alistair puts it, "some pretty extreme things". The Wardens will, in these circumstances, accept former or active Blood Mages, burn down innocent villages in order to protect more vital ones, potentially side with and thus gain contingent of Werewolves to help defend cities, authorise the creation of Golems (who are completely self aware, but have no free will), and will forcibly recruit people into their order, even Loghain.
Awakening gives you the option to either save the Warden stronghold of Vigil's Keep or the City of Amaranthine at the expense of the other. It's potentially possible to do both and keep all of your companions alive afterwards, but this is not easily done. There is also the option to keep the Architect, a sentient Darkspawn, alive so he can continue his research into removing the Hive Mind connection the Darkspawn have to the Old Gods hopefully preventing future Blights..
Dragon Age II has the option to choose between various backstories of the first game. The full-on Knight Templar option is by no means light, aptly titled "No Compromise".
In Dragon Age II, Anders eventually becomes one of these, due to becoming an abomination and fusing with Justice, turning the spirit into Vengeance. The influence of Vengeance, coupled with Ander's hatred for the templars and bitterness toward the oppression that mages suffer under, means that Anders/Vengeance is ultimately driven to plot a terror attack on the Kirkwall Chantry to force the conflict into an all-out war.
Knight-Commander Meredith, the leader of the Templars' Kirkwall division, is the very embodiment of the Knight Templar archetype, resorting to whatever means she can to ensure that mages don't go out of control, considering it her painful but righteous duty to suppress any free will that mages might exhibit, all the while rigidly clinging to her faith in the Maker and her position as His 'humble servant'. She falls into a short crisis of faith during the final battle, when she is close to falling, but instantly reassures herself that the Maker is with her, and continues the fight with renewed zealous conviction.
Even before Meredith, you had Ser Alric, who proposed a "final solution" to the mage problem in the form of making ALL mages Tranquil. And, from the start of the game, we had Sister Petrice. At first, she's content to get someone killed in order to highlight how "barbaric" the Qunari are and what a blight they are to the Chantry, but she takes this several steps higher when she murders the Viscount's son in cold blood because A) he was a convert to the Qun, and B) to set up a False Flag Operation about a Qunari supporter (Hawke) having killed the man while he was in the Chantry itself repenting his sins and coming back to the fold.
Dragon Quest VIII has an order of zealous knights who are actually called the Templars.
This is ultimately a subversion, as the leader is more concerned with seizing power than he is with enforcing the Goddess's will.
In Drakengard 2, Nowe's friend and fellow Knight of the Seal Eris is a definite Knight Templar at first, rationalizing her superiors' questionable actions, threatening to harm Nowe when he expresses doubt about the Knights' righteousness, and sporting a disturbing smirk when about toburn Manah at the stake. Luckily, she wises up eventually...even if it took General Gismor using her as a human shield and leaving her to die for her to do so. Gismor himself does not fit the bill: he doesn't care about justice or order, only personal power.
In the 2-D Fallout games (Fallout, Fallout 2, and Fallout Tactics), the Brotherhood of Steel fits this trope quite well. The California branch (Fallout/Fallout 2) is dedicated to recovering Lost Technology from across the Scavenger World they live in, and they refuse to help anyone who is not part of their organization, even when it would not even hurt them to lend a hand. The Mid-Western branch (Fallout Tactics) set themselves up as post-apocalyptic feudal lords who will go to any ends to ensure justice—though they're better than the other factions trying to control the Mid-West, all of whom are either insane or outright evil.
In Fallout 3, the Washington, D.C. branch abandoned the Knight Templar dogma of their founders and have put their resources towards defending the Capital Wasteland from the Super-Mutants. However, some of them disagreed with this shift in policy and formed their own group called the Brotherhood Outcasts—their goals are more in line with the original Californian Brotherhood of Steel, which is to say, more selfish.
However, by the time of Fallout 4, the East Coast Brotherhood (including the Outcasts who rejoined) has reverted to be more like the West Coast chapters, but while still wanting to protect wastelanders and with some concessions towards pragmatism. (such as continuing to permit the recruitment of wastelanders) After Elder Lyons and his daughter Sarah died (Owen of old age while Sarah died in combat), Arthur Maxson took control of the chapter after being appointed Elder by the West Coast Elders. They now regard all feral ghouls, super mutants, and synths as abominations that need to be wiped out because of their threat to humanity, regardless of the fact that some of them (mostly synths) are just regular people no different from normal humans. In the case of synths, some don't even know that they're synths.
This becomes an issue in Fallout: New Vegas where the Mojave branch of the Brotherhood is crippled by their xenophobic and isolationist nature, to the frustration of Veronica, a scribe who wished that they'd actually do something progressive with their tech. In fact, if she chooses to join the humanitarian Followers of the Apocalypse at the end of her companion quest, it ends with a few BoS members murdering an entire outpost of Followers and trying to kill her in turn for possibly spreading information and traumatizing her horribly in the process.
Outside of the Brotherhood, we have President John Henry Eden, who just wants to "rebuild America"...by wiping out anyone with a trace of mutation, even benign or unnoticeable ones. Since radiation is so pervasive in the world of Fallout, and since radiation mutates whole organisms (rather than individual cells) in this world, President Eden's plan would kill many more people than it would actually save. Exactly how he intends to help Americans rebuild their country by killing them all is never explained. A smart or charismatic enough Lone Wanderer can actually point outthis logical flaw in his plan, convincing him to self-destruct.
In New Vegas, there's Sheriff Meyers, one of the three possible sheriffs you can recruit for the town of Primm. His swearing in speech is simply "Be good...or I'll shoot you dead."
The game heavily implies that recruiting Meyers is the ideal solution to the city's quest, though the endings will differ greatly, depending on what a player considers a 'good' outcome. If the player does recruit Meyers, the ending slide will note that he keeps Primm peaceful and safe.... but also notes that every now and then, when there's no solid evidence against a known troublemaker, that person will turn up tragically and accidentally dead the next day.
Another New Vegas example comes from the Honest Hearts DLC: Joshua Graham, also known as The Burned Man. A Mormon missionary sworn to protect the Dead Horse tribals and the co-founder and formerLegate of Caesar's Legion, even as The Atoner, he's a vicious General Ripper absolutely one hundred percent okay with wiping out another tribe down to the last man for posing a threat to them - not just fighting them off, but destroying them utterly, including cold-blooded executions, if need be. Apart from that, he means well. And the tribe that he wants to wipe out did massacre his people, want to join Caesar's Legion, and celebrate rape and murder. So Joshua does come out looking better...in comparison, at least.
It's strongly implied that Graham actually enjoys killing, which doesn't make him much better then the Legion or the White Legs, adding that double dose of hypocrisy frequently seen in a Knight Templar. However, depending on how you deal with him he may come to acknowledge that he's been lying to himself the entire time to justify his desire for vengeance against Caesar.
Pacer is a Token Evil Teammate to the Kings (literally, he's the only one with Evil karma) who thinks that the best thing for Freeside and the Kings is refusing anything that remotely resembles external control out of their territory, with no qualms about resorting to violence first and often to do so. His dogmatic pigheadedness leads to him singlehandedly nearly starting a war between the NCR and the Kings, which already gets several Kings killed to begin with and can escalate to the Kings being wiped out by the NCR and leaving Freeside civilians vulnerable to exploitation as a result.
Subverted in Final Fantasy Tactics, while your main enemies in the game are the Knights Templar of the Church of Galbados, and the Church itself claims to want to destroy the monarchy and create a world of equality; in reality, the Church was founded by a demonic war lord, who, if resurrected, would bring about the end of civilization. The Big Bad is also known as the Angel of Blood.
Final Fantasy XII's supplemental material expands upon Ivalice's mythology and reveals that the so-called bad guys were grotesquely wronged and exploited servants of the Gods (Cu Chulainn/Queklain and Zodiark first and foremost) who have it in for the Gods who caused them so much misery. And the Bloody Angel was the Head Angel serving the Gods, and was so disgusted upon discovering how the Lucavi were treated that she went off the deep end and went Knight Templar on her masters as well. In fact, Altima is the only one of the Zodiac Stone spirits to NOT be a Lucavi - the Virgo stone is associated to a different being among the Lucavi, which is never seen but is implied to have played a large part in Altima's...well, would that be a heel-face turn or a face-heel turn?
His superior, Grand Maester Yo Mika, is a variant, in that he actually wants to preserve the vicious cycle and is willing to do anything from lying to forced marriages to murder to achieve it. He doesn't actually agree with what Seymour wants to do (Auron mentions at one point that Mika and Seymour are "not of one mind", while in another, he talks about how Mika wouldn't approve of what Seymour ultimately wants) and genuinely thinks that there's no other way to stop Sin from destroying Spira besides forcing summoners to perform their Senseless Sacrifices. Nor does he think that the people of Spira are capable of governing themselves without the Church of Yevon telling them what to do, claiming that enlightened rule by the dead clergy of Yevon was better than the "misguided failures" of the living.
The goddess Ashera from Fire Emblem: Radiant Dawn. About 700 years prior to the events of the game, the world made a covenant with Ashera. She would sleep for 1,000 years, and if she is awoken by war, she would destroy the world without hesitation. She was awoken when her counterpart Yune was freed from the titular MacGuffin, so she turned 99.99% of the world's population to stone instead. Those who remained fought back, so she freed some people, gave them blessed arms, and sent them after the survivors. This turns out predictably, since one of the survivors is Ike.
In the Five Nights at Freddy's franchise, the Puppet fits the Trope. As revealed in 3, it is inhabited by the soul of a murdered child (possibly the first victim of the Murderer) and its goal throughout the whole franchise was vengeance on the Murderer. It was responsible for turning the animatronics murderous in the first place and binding the spirits of the murdered children to them in an attempt to kill its enemy. Unfortunately, they and the Puppet itself wound up killing a lot of other security guards too.
As their name implies, the Templars from the The Secret World are this. They are however, a downplayed example of this trope, as they aren't portrayed in a very negative light despite being terrifyingly overzealous with the destruction of all evil.
Helios from God of War 3. In the third game, he is not only very determined to destroy the Titans (his own kind in the original Greek Mythology) so that they can't triumph, but also remarkably loyal to Zeus even after revealing himself to be something of a coward. This loyalty causes extremely poorly made decisions that result in his death. Also, of all the gods in God of War 3, he is the only one who has no personal reasons to attack Kratos.
The White Mantle of Guild Wars sacrifices people who have the ability to open a gateway to the Realm of Torment to power the seals keeping the gateway closed. Their gods, the Mursaat, also qualify, although they're also motivated by self-interest; a prophecy says that when the gateway is opened, they'll be wiped out.
Forerunner Warrior-Servants held this view of the Mantle of Responsibility: "The Forerunners are the rightful guardians of the galaxy; therefore anyone who stands against them is automatically in the wrong and must be destroyed."
In Halo 5: Guardians, it's revealed that the revived Cortana seeks to bring peace to the universe by attaining the Mantle and ruling as a tyrannical authoritarian. By using the Guardians, she plans to use their power to annihilate species who don't adhere to her moral authority.
Lt. Carter Blake in Heavy Rain qualifies, considering the fact that he beats suspects to get answers and tries to kill an innocent man because he thinks that he is the Origami Killer.
Blake is actually more along the lines of a simple Dirty Cop and just plain Ax-Crazy. Considering the fact that he has no regard for the actual guilt of the suspects and simply wants someone behind bars for the killings, it's very possible he's just looking for a promotion. That, or does play the trope straight, just while being insanely careless and moronic.
Goldman from House of the Dead. Okay, so his goal is to protect nature from man's depredation. That's a noble goal and quite understandable. Then he says that he plans to do this by returning man to his "natural state". Pretty worrying, but not that villainous. And then he mentions that he plans to accomplish this via a Zombie Apocalypse. Okay, now that's taking things a little too far.
Superman - or rather, Regime Superman - in Injustice: Gods Among Us embodies this trope perfectly, as the fallen Man of Steel shows us how dark an innocent, idealistic hero we know and love can turn should he lose the ones he cherishes and subsequently push his "justice" too far. He starts by murdering Joker, who tried to push him into that and succeeded, then forcibly stopping all wars, then killing entire invasion force from Apocalypse, then creating world-scale dictatorship to protect Earth's people. He also started hunting all those who oppose or resist him, including his former friends and innocent people, and often murdering them. His supporters from fallen Justice League are this too, to different extents.
Count Vulgar— er, Veger from Jak 3: Wastelander certainly deserved a place. He didn't like Dark Eco. That was OK, nobody particularly liked Dark Eco. However, he exiled and repeatedly attempted to kill Jak, whose Dark Eco powers let him save the world at the end of the previous game. He even described himself as "the glorious light that burns away the shadows" in between attempts to turn Haven City into a totalitarian theocracy under his rule, subverting Utopia Justifies the Means because it wasn't really going to be that much of a utopia with a psychotic zealot like Veger in charge.
Knights of the Old Republic II has Jedi Master Atris. She is more extreme than most of the Jedi council, wanting the Exile to be punished even more than s/he was, arrogantly dismisses everything she doesn't agree with as being of the Dark Side, and during the events of the game, claiming to be the only true Jedi left. She is even willing to call a conclave on Katarr without attending, to lure out the enemy that was hunting them. As a result, Darth Nihilus devasted the entire planet. Unfortunately, in her efforts to fight the Sith, she has unknowingly fallen to the Dark Side.
Just to push the point at how righteous he is, we have Ky Kiske from Guilty Gear and his Knight Templar-tastic theme "Holy Orders (Be Just or Be Dead)". He gets better.
Leo from Lunar: Eternal Blue starts off as this. Thankfully, he is more open-minded than most other examples of this trope and once he realises that the church he works for is actually trying to resurrect the dark god, he switches sides.
Saren, the villain/Dragon of Mass Effect, was an extremely violent Knight Templar during his tenure as a Spectre, prior to the events of the actual game, where he became more of a Dark Messiah.
In Mass Effect 2, the asari are shown to have a group of Knights Templar, the Justicars. Sworn to obliterate evil and corruption wherever they find it, they are lauded as heroes (heroines?) for their exploits and dedication, but most asari would rather not have them in the immediate vicinity due to their rather strict definitions of "corruption" and their reputation as merciless killers. Having one on a planet outside asari space, where they could interact more readily with other species, is seen as a diplomatic disaster waiting to happen.
Subverted by recruitable character Justicar Samara. As seen above, Justicars have a reputation for mercilessness and extremism in the pursuit of justice, but when you meet Samara, she turns out to be rather reasonable. Although she still follows the Justicar code to the letter, Samara is content to use Loophole Abuse to avoid harming innocent people if at all possible. And she is willing to work with Renegade Shepard because she recognizes the larger threat, but does tell him that if they ever cross paths afterward, she will kill him/her (she, obviously, has no problem working with Paragon Shepard).
A notable example of her Loophole Abuse occurs in the third game, when the monastery where her two living daughters reside is destroyed with one of her daughters killed in the process. Her daughters suffer from a rare genetic condition among Asari that turn them into essentially sexual serial killers that can seduce anyone but kill them in the process and voluntarily lived in the monastery built for Asari of this condition to allow them to survive safely outside of society. The Justicar code doesn't allow any Asari with this condition to live outside the monastery so with it destroyed she has no choice but to kill her last living daughter, and instead points her gun at herself to avoid the conflict. Shepard can prevent her suicide and propose an alternative.
Garrus is this in Mass Effect 2. Before you pick him up as a party member, he is under the guise of Archangel, who, with a squad, murders his way through the criminal underworld of Omega. He's still a badass, but he is not too worried about killing criminals anymore.
The main villains of Master of the Wind, the Hand, are a religious cult that fanatically believes that humans alone deserve to rule Soleste, and all nonhumans must be subjugated. Most of their forces consist of "holy" people who utilize light magic, and throughout the series they claim to be the "chosen of Arcadius" and that their actions are "spreading his divine will". It turns out at the end that its all a farce. While the Hand's leader fanatically believes in the cult's message, The Dragon, who turns out to be the real power behind the Hand, doesn't actually care about Acradius' "message", and started the Hand purely so she could revel in the power she would have once they took over the world.
The Robin Academy, a secondary villainous faction, are also an example of this. Initially founded by Stoic's archrival Dobsen Robin to more effectively battle him, in the present day it has evolved into a secular academy of Light Mages that preaches for its students to hunt undead, as well as shun the rest of Soleste for their acceptance of undead (except Vampires). On a whole though, they don't end up being much of a threat, and unlike the Hand, their zealotry is so over the top and bombastic that its almost comical.
X and the Maverick Hunters start to fall into this in Mega Man X 4 and X5. Fast-forwarding 100 years to Mega Man Zero, Copy-X is protecting humans by mass extermination of innocent Reploids. Had it not been for the Executive Meddling of Keiji Inafune by Capcom, it would have been the real X himself who became such a villain.
Over the course of the Metal Gear Solid series, it turns out that the Patriots, the amoral organization controlling the government, was founded by a benevolent group of people who only wanted to change the world for the better. However, their leader became so insistent on keeping order, he started resorting to more and more questionable methods, finally leaving control in the hands of A.I. units that did not put any value on human life.
In Might and Magic VII, there are clear signs of some back-story between the good Church of the Sun and the evil Church of the Moon, showing that the Church of the Sun put too much emphasis on defeating the Moonies and not enough on, for instance, taking care not to leave too much of Erathia and its environs a seared wasteland.
Hotaru from Mortal Kombat: Deception is fanatically devoted to order. In the game's story mode, he imprisons the main character (who had been allied with him) for unknowingly breaking curfew...and decades pass before he gets his appointed trial.
So much as sleep in public in Daggerfall and you've suddenly got guards crawling out the woodwork, all of them shouting at you to HALT!
If there were a poster child for this trope, it could be the Ordinators from Morrowind. They are the militant wing of the Tribunal Temple and do not tolerate outsiders. Walking past them will usually net you the "We're watching you...SCUM," response. Even if you become the new head of the Temple, the indirect boss of the Ordinators, they don't become much more tolerant. And may the gods help you if you mention the Nerevarine prophecy around them. Or wear their armor.
Oblivion? Probably due more to the game's AI for them, but so much as touch something that doesn't belong to you and — STOP! YOU'VE VIOLATED THE LAW!!!!
Averted by the guards in Skyrim, who are much more loose than previous guards to the point that they'll simply ignore you if your bounty is low. The Vigilants of Stendarr, a group dedicated to hunting down daedra and monsters can lean towards this.
Vigilant of Stendarr: Walk always in the light, else we will drag you into it.
In Arcanum, the Big Bad intends to cause the death of every living thing in order that they may enjoy the peace of oblivion.
Vhailor from Planescape: Torment is a member of the Mercykillers, a Planescape sect that believes in the absolute order of the law. Crime is violently punished, and rehabilitation is often not under consideration - their creed is thus: "Justice purges evil. Once all have been cleansed, the multiverse achieves perfection."
For more fun involving Vhailor, check out the quote page.
Just to help put things in perspective, Vhailor is no longer a man, but a haunted suit of armor an incarnation of justice who exists through the strength of his Mercykiller beliefs.
The Mercykiller faction formed when the Sodkillers (a gang preying on the Clueless) joined forces with the Sons of Mercy (a group of law-upholding citizens, some of them paladins) for unspecified reasons. The faction lived up to this portmanteau name (they kill mercy), becoming the semi-official and extremely corrupt police force. Vhailor is remembered many years after his disappearance because of his fanaticism, showing that Knights Templar are very rare among the Mercykillers. Or that Vhailor was considered insane even by Knight Templar standards.
Cyrus from Pokémon Diamond and Pearl is out to create a world without war or conflict. To achieve this, he plans to destroy the current universe and rewrite it from scratch (possibly without emotion, depending on which version you play). At heart, he's still a pacifist, but boy does he know how to stretch the definition of that.
Pokémon Black and White's Team Plasma take the definition in its most literal form — the members are dressed as Crusade-era knights, complete with Chi Rho on their chest cloth, and they claim that their mission is to "save" Pokémon from human enslavement. They look the part, for sure, and the methods involve theft to carry this out, so acting the part's guaranteed. It turns out that Team Plasma doesn't follow this trope one hundred percent — it's all a front for Ghetsis, one of the Seven Sages, to conquer Unova and be the only one allowed to use Pokémon. It is ambiguous how many Team Plasma members were truly in it for the cause they claimed — the only one for sure being their figurehead leader and Ghetsis's son, N — who's the least evilof the lot.
"...Everyone will eventually pay for what they've done."
Ironically, he's a Karma Houdini himself...Until Jack Marston avenges his father.
Ishida Mitsunari from Sengoku Basara is out to avenge the death of his liege lord at the hands of the villainous Tokugawa Ieyasu, and believes himself to be the only righteous person (aside from his friend Yoshitsugu) in Japan. All those who will not repent their villainous ways and join his noble cause are vile betrayers to be cleansed as the sinners they are. From anyone else's point of view, Mitsunari is an extremely fanatical and angry man lacking a purpose in life beyond his revenge, and Ieyasu is, for the most part, a (slightly hypocritical) Love Freak whose repeated attempts at reasoning with Mitsunari only makes Mitsunari angrier.
Shadowbane has the Temple of the CleansingFlame, who get literal templars as a pert of their class options.
The Shin Megami Tensei series in general has Knight Templars up the ass; if a character is on the Law side, there's a very strong chance that they'll be one, especially the Angels and the Order of Messiah. Some examples:
The Law Hero gets to be like this near the end of Shin Megami Tensei I, and all the higher-ups on the Law side of the spectrum (who are all worshippers of the Path of Inspiration) are a version of this - including the protagonist, if the player so chooses.
Averted with Remiel and Amane, along with the game's take on God. God and pals are quite willing to support humanity's existence; it's just that they've put humanity on trial to see if they truly deserve the power. Should you follow Amane's ending path, you go on to become the Messianic Archetype, leading humanity in God's stead.
Of course, if you take Naoya's route in the Updated Re-release, the angels go right back to smiting anybody who opposes them.
Notably, in Shin Megami Tensei IV, Mastema returns, but this time as quite possibly the most understanding incarnation of the Law faction in the franchise. If his beliefs are right, God is also no longer a Knight Templar and the archangels are just insane.
The ending for Siegfried in SoulCalibur IVcauses him to say, after defeating Nightmare, "With this... it ends." "Our kind must not exist in this world; not ever again." This causes SoulCalibur to crystallize him, Siegfried, and Soul Edge...as the screen fades to black, the epilogue says that the world will soon be "covered in crystals, making it a utopia without wars or suffering." Whether this is Siegfried's choice or SoulCalibur's is unknown.
Cassandra's ending makes it pretty clear that SoulCalibur has a serious Knight Templar streak. She is so fed up with what her sister, Sophitia, has become because of SoulCalibur that, after destroying Soul Edge, she destroys Soul Calibur as well.
Confirmed in SoulCalibur V: Soul Calibur fakes Sophitia's form to manipulate her son Patroklos to kill his sister Phyrra, the wielder of Soul Edge. After unleashing its true power, the sword subtly mind controls him to assure him he can't save her, and when he kills her, the sword dumps his soul into a void while it turns the world to crystal. After the Edge Master hits the Reset Button, Patroklos sees through the illusion and Soul Calibur gets infuriated at his defiance of its goals and tries to kill his spirit so it can take his body by force, and manifests itself as Elysium, the True Final Boss of the story mode. Light Is Not Good indeed.
In S.T.A.L.K.E.R. - Shadow of Chernobyl, the C-Consciousness Project is this. Conceived to rid the world of all destructive and negative human emotion, its members accidentally cause a spatial tear that causes the several kilometres around its site to become a desolate, radioactive wasteland fraught with dangerous mutants ("The Zone"). To prevent discovery of their project by those seeking valuable artifacts in The Zone, they use various devices that result in death and/or zombification of those who come near. Anyone who makes it past is diverted to what is believed by all to be an omnipotent wish granting device, but in reality, it brainwashes the wisher into becoming a minion of the project, either as part of the official death squad, or as mindwiped individuals who have a singular mission to carry out, but aren't sure why. The player character begins as one of these individuals.
The Duty faction constantly preaches about the horrific dangers of the Zone and works strenuously to prevent the spread of its corruption from the outside world. In Call of Pripyat, however, it is revealed that they're not what they claim to be: a quest involving a strange anomaly at an abandoned water cooling station in the second map of the game reveals corpses of Duty stalkers being spat out to the ground once a special detector has been acquired. Among the bodies is the original founder of the faction, whose PDA reveals that the faction's original purpose was literally no different than that of any opportunistic Stalker hoping to snag his riches in the Zone.
Despite the name, the Protoss High Templar from StarCraft may or may not be like this. But one of the major characters, Aldaris, is a Knight Templar to the core. At first, he didn't care whether Tassadar was contacting the Dark Templar for the good of the Protoss race in general because he knows that they are the only ones who can destroy the Overmind; he violated the Conclave's orders, so he must be arrested. Before that, during the Zerg and Terran campaigns, he ordered the destruction of all life on any planet with a Zerg presence. He got better after seeing Tassadar and Zeratul's efforts (also Raynor's) to defeat the Overmind and started supporting them, but in Brood Wars, once again, he acts as a Knight Templar, refusing to work with Kerrigan while the others had no choice but to ally with her. Unfortunately, this is the only time where his actions were actually RIGHT. And he's killed soon after. By Kerrigan, who reveals that she's been using the rest of the Protoss the whole time.
The Zerg Overmind, with its will to infest everything— especially the Protoss— in order to create the perfect species, might also count. [[spoiler: Partially. The rest is Brainwashed and Crazy from Amon,its creator.
The UED from the expansion pack definitely are this: they just want to protect the Terrans, but that really means A) taking them over and B) wiping out all opposition, thus, making enemies of everyone.
The best part is that Aldaris was Judicator caste not Templar caste.
The AI ODE System from Super Robot Wars is an AI example of this. When its creator, Wilhelm Juergen, had a breakdown, it got reprogrammed to gather humans together in one network to protect Earth from aliens. It took its orders very literally and went on a mass kidnapping and absorbing spree, eventually going after its creator.
Yggdrasill from Tales of Symphoniaset out to resolve a war between two magitek nations and end the world's Fantastic Racism, creating a world where everyone could be free of discrimination. One dead little sister later, he's accomplishing this by splitting the world in half, grinding the humans into the dirt, and killing them off to create Metaphysical Fuel that would turn the half-elves into soulless, mindless, and lifeless beings. It never even occurs to him to consider that he hasn't got the moral high ground.
Grand Maestro Mohs from Tales of the Abyss is a devout follower of The Score, a set of extremely specific prophecies that say that there will be a time of great prosperity following a massive war between the two dominant countries, a war that he has tried to incite numerous times. To do this, Mohs collaborates with Master Van, the real villain of the game, who has conflicting interests with Mohs and is more of a Well-Intentioned Extremist.
The Catholic Church as depicted in Tsukihime and, to a lesser extent, Fate/stay night (where the Knight Templar would probably more be Emiya Kiritsugu, since the church is mostly connected with Kotomine here) is obsessed with killing all vampires and other non-humans. A prime example is when Ciel resurrected for the first time: they killed her for a month straight, nonstop and rather messily, before giving up because she cannot die while Roa lives. They also appear to have a mild hands off/Enemy Mine approach regarding Arcueid...mostly because there is no way they could possibly kill her and they don't want to make her mad.
In Ultima V, Lord Blackthorn usurps Britannia's throne and turns the virtues, formerly self-imposed moral guidelines, into enforced laws (for example, forcing the people to donate to charity or face execution). The results are predictable.
This, arguably, is also one of the reasons why humility is considered the final, eighth virtue in Ultima. Despite not being directly based on Truth, Love, or Courage, the game says that Truth, Love, and Courage cannot exist with the virtue's opposite, Pride.
The Warcraft series is filled to the brim with these.
In Warcraft III: Reign of Chaos, Arthas Menethil starts out as a headstrong young man fighting the undead. Things start going downhill when he slaughters the populace of a major human city to avoid the plagued parts of it from turning into the undead. Later, when his father, the King, commands him to come home from an expedition in the home continent of the Scourge, he has hired thugs sink his own ships and blames the whole thing on them to get an excuse to disobey the order. Eventually, he lets a good friend die in exchange for a sword that can defeat the demon he thinks is behind everything. At which point he stopped being a Knight Templar wanting to save his people and turned into an avatar of vengeance is a hotly debated topic. Some fans will avidly debate that he never stopped being a Knight Templar, given several of the views the novel revealed him to have, and the fact that after mentally reliving his actions up to the point of reawakening, he decides that he would not change, as he still believes that he made the right decisions. Rather, hisfear offailure prevents him from fully realizing his own evils, even when he briefly questions himself, because to change his mind or path is to admit that his first choice was wrong, which is failure. His calm sanity and acceptance of death seems to support that he was never truly evil. Great, so JainaWAS right, but by the time she knows, it's too late.
In the Expansion Pack for the same game, Frozen Throne, Maiev Shadowsong devotes her entire existence to hunting down Illidan Stormrage, whom she had been tasked to guard during his imprisonment. She eventually lies to the man who gave her this task in the first place that his wife is dead so that he would help Maiev capture Illidan instead of going to save her from certain peril. In World of Warcraft, she manages to fulfill her purpose, only to realise that her life has no meaning anymore.
Daelin Proudmoore's quest to exterminate the orcs in Frozen Throne also matches this trope.
Meanwhile, World of Warcraft has the Scarlet Crusade, an organisation bent on destroying the undead. Over the years, they have become so paranoid about the Plague which turns people into members of the Scourge that they will attack anyone they do not recognise as a member of their organisation. Ironically, their leader, and the man who sent them down the slippery slope, is a demon in disguise, manipulating them for the sole purpose of creating a force to destroy the Scourge.
The Burning Crusade expansion introduced The Ethereum, the former Ethereal ruling class who declared war on The Void (and especially Dimensius) after the latter destroyed K'aresh, their homeworld. The Ethereum have become so consumed by their mission that they consider anyone who doesn't help them an enemy and have even gone to the point of infusing themselves with void energy to create nexus-stalkers, which often end up destabilizing and becoming voidwraiths.
Kael'thas Sunstrider's goal was to satisfy his race's addiction to magic after the Lich King corrupted the Sunwell. He aligned with Illidan and built the manaforges for this reason - to provide the blood elves with a new source of magic to replace the corrupted Sunwell. He did not become truly evil until after his first resurrection.
Later on, in Wrath of the Lich King, the Blue Dragonflight under Malygos also turn into this - willing to kill tens of thousands and cause irreversible ecological damage to the planet to rid the world of mortal arcane spellcasters. The Red Dragonflight and Kirin Tor agree that continued mortal use of magic will destroy Azeroth. The Blue Dragonflight is simply taking the direct approach to solving the problem.
Judging by the fact that the Titans created a being called Algalon the Observer to serve as a fail-safe protocol that would "re-originate" (read: annihilate all life and start over) the world and have every intention of using it, they probably qualify as well.
The Mogu are the definition of Abusive Precursors whose crimes consist of Cold-Blooded Torture, Necromancy, And I Must Scream, Would Hurt a Child and every trope that crosses the Moral Event Horizon. If Lei Shen's words are taken at face value, they genuinely believe themselves to be continuing the titan's work by bringing order to the races of the world that were native to Azeroth or diverge from the titan's plans, and it's implied the titans themselves wouldn't exactly be upset how the Mogu go about things.
In Borderlands 2, Handsome Jack has dedicated himself and the near-limitless resources of the Hyperion Corporation to bringing order, civilization, and peace to the lawless planet Pandora. Unfortunately for Pandora, Jack's idea of "order, civilization, and peace" is a fascist police state under his absolute control where crimes like profanity and littering are punished by death. He's also a despicable hypocrite personally who is convinced he really is the hero of the story, yet he engages in slavery (including enslaving his own daughter!), wanton murder (including a mandatory execution lottery in the town of Overlook) and gleefully murders and tortures people personally (though he periodically lets them survive because "That's what heroes do: We show mercy."). He spends the entire game being utterly convinced that he's still the hero, right up to his death.
Borderlands: The Pre-Sequel! takes a different angle with Colonel Zarpedon, who is more than willing to destroy Elpis and everyone living on it in order to save the rest of the universe from destruction. "Thousands to save millions" is one of the Lost Legion's mantras.
Calidor Antevian of WildStar believes he is merely spreading the good word of the Eldan by turning everyone into cybernetic, brainwashed monstrosities. He sees anyone preventing the spread of "the Truth" as a heretic to be destroyed.
In Rebuild 2 and Gangs of Deadville, the biker gang known as the Last Judgement have this sort of mentality. They believe that the end times are upon them (which the diaries note is actually true) and thus set to cleanse the world of zombie and human alike. If you're alive, you're probably a sinner, and that's all the excuse they need to roll in and raid your fort, or harass friendly gang The Riffs. On top of this, they're total hypocrites that enslave women.
In Telepath Tactics, Scarlet Etolie has shades of this. Emma is able to keep her reigned in, but some of her conversations with the other party members can be a little terrifying.
Scarlet: Brigands are a plague upon this isle. It's not for nothing that I have sworn to wipe them out... Tremolo: Everyone's gotta eat, love. Scarlet: Not after I'm through with them, they don't.
Civilization: Beyond Earth: Everyone. All three of the ideological Affinities have some religious flavour to them in a straight Aversion of Outgrown Such Silly Superstitions, and all civilisations will attempt to impose their chosen ideology on everyone else, violently if necessary. A Harmony Civ's end-goal is to invoke an Assimilation Plot and force all it's members into a psychic connection with the planet, with a very questionable tolerance for individual autonomy. A Supremacy Civ's end-goal is to invade- sorry, liberate the Earth and it's people from their highly flawed fleshy bodies and forcibly upgrade them to superior forms. A Purity Civ's end-goal is to exterminate the native alien life, including any of their transhuman counterparts, and terraform the planet to make room for Earthling settlements, in a disturbingly similar fashion to Generalplan Ost, the Nazi plan for genocide and recolonization of Eastern Europe.
In Diablo III the Templar Order are an order of holy warriors based on the Zakarum faith, "redeeming" criminals by blinding them to their sinful pasts and setting them upon a new path dedicated to the Light. Except the initiation that blinds them to their pasts involves days of Cold-Blooded Torture and brainwashing by the Templar's Inquisitors, and the Order doesn't really give a blessed shit about a promising initiate's guilt or innocence — as evidenced with Kormac, your Templar companion, and Jondar, an enemy you take down early on in the game, they will gladly pile false crimes and sins upon someone they deem worthy of becoming a Templar. You ultimately have to destroy the Order during the course of Reaper of Souls when they announce their intent to turn every citizen of Westmarch and beyond into Templars, with all the horrificness that this entails, in order to "lead mankind into the Light", making it clear that the Grand Maester's true goal is to enslave humanity.
Many of the angels have this attitude, feeling any being of demonic origin must be exterminated. In the past they voted on destroying humanity because of their half-demon, half-angel heritage and barely decided to spare them.
The Engineers in Splinter Cell: Blacklist, who are trying to force the U.S. to pull their military forces out of all foreign countries they are currently stationed in (All 153 of them) in retaliation to atrocities America has committed in those countries and/or the belief that American influence is corrupting/has corrupted those countries by unleashing devastating terror attacks on major U.S. cities. Notably, some of the Engineers themselves are American.
Grünfeld Bach in Vampire: The Masquerade – Bloodlines is a holy warrior with an unwavering drive to destroy "agents of Satan" like vampires, LaCroix in particular. Unfortunately he's a-okay with Van Helsing Hate Crimes, doesn't mind collateral damage like burning down or blowing up an inhabited building to get one vampire, and kills at least one of his own men for disputing orders.
Namm from Nexus Clash is the in-universe god of this trope and proud of it. He's bogged down in an aeons-long war with the Manipulative Bastard demon lord Tlacolotl and has shown no hesitation about slaughtering countless demons, anyone who tries to sit out the war and even a member of his own angelic pantheon in his boundless zeal to win. What makes it that much worse is that Tlacolotl really is that much of a threat.
Lex, the Hand of Justice from Paladins is a lawman who talks about how malevolence is like a sickness and that he will cleanse the world with his judgment. And by judgment, we mean his magnums. "No one escapes THE LAW!"