What it ultimately boils down to. In theory. But since it's so much fun to argue...
Character Alignment is a shorthand for a given character's (or religion's, society's, organization's, etc.) moral/ethical outlook on life, the universe and everything. Many roleplaying games use some sort of alignment system as a Karma Meter, an "ideal" for a character to live up to, or just a descriptive shorthand for characters, though some gamers deride them as crutches to "real roleplaying," and some systems accordingly have none at all.
Always remember that the vast majority of characters in fiction are not tabletop game characters, and therefore lack a canonical interpretation of alignment by the standards below. Characters should only be categorized under them when their alignments are clearly and explicitly stated in canon. As both the standards and especially character personalities are vague, complicated to interpret, and subject to change with Character Development, thus leading to endless debate, the assignment of alignments to characters not stated to have them is considered strictly subjective.
The alignment system most roleplayers are familiar with is the one used in Dungeons & Dragons, which has appeared in a couple of different forms:
The original editions of Dungeons & Dragons drew on the works of Poul Anderson and Michael Moorcock to come up with three alignments: Lawful, Neutral, and Chaotic, with Lawful representing honor and obedience to, well, law. Chaotic characters may be insane, but could lean towards a desire for the freedom to do what they want. Whether they do good or evil because of this freedom is what decides their moral leaning. Neutrality alternatively represents neither one (as was the case with animals and people who simply didn't care) or a desire to see "balance" between the two. Later editions kept this as the "ethical" axis of the alignment scale and added a second "moral" axis of Good, Neutral, and Evil.
The ethical axis was more one's attitude towards the position of society and rules: Lawful characters think having an ordered society is important and beneficial; Chaotic characters don't necessarily oppose this but think the freedom of the individual comes first; Neutral characters tend to judge such situations on a case by case basis. If a law was unjust, a lawful person might think it needs retooling, or say that it prevents more problems than it causes. A neutral person might see the need for such a law, but would still think it should be scrapped and redone from scratch. A chaotic person would probably just break it.
This is sometimes lumped in with two different attitudes: whether the character in question believes that the universe as a whole is orderly, and how the character conducts his life, with plans or flying by the seat of his pants. This can produce considerable confusion, as the three levels can exist in any combination.
The "moral" axis can be adequately explained by the focus of those morals: Good people generally focus on you (they feel that they should help everyone else when possible). Neutrals are usually focused on us, meaning their family and friends (they can be charitable, but their "circle" always comes first), though they can display elements of me (in that they tend to look out for themselves and are uninterested in the affairs of others). Evil people are generally me focused (often at the expense of other's misfortune). However, like good, evils can also focus on you (but instead of aid and kindness, when those who are evily aligned focus on others it is with an emphasis on destruction and suffering).
Combining the two axes allowed characters to be of nine possible alignments, as follows:
Lawful Good: Basically, they believe Law is Good, and that you do good by upholding the law. The alignment of The Cape, Paladins, and the Knight in Shining Armor. Believes in Truth, Justice and such, but may potentially believe in them a little too much. Poorly portrayed, he tends to be Lawful Stupid, largely depending on your interpretation of "good". Individuals who believe that Rousseau Was Right will tend to view society as tending towards Lawful Good, with most individuals within it as lawful or Neutral Good. In D&Dcanon up to the most recent edition, archons, celestials who inhabit the Seven Heavens, are Lawful Good. From a non-D&D more realistic perspective however, LGs are likely altruists who believe in an orderly lifestyle for the benefit of their species.
Chaotic Good:Rebels and free spirits who are stereotypically found opposing tyrants and other oppressive types. Somewhat like Chaotic Neutral, only much nicer. They tend to believe that things like order, discipline, and honor get in the way of doing good. Or they may believe too much order is bad for everyone. Whatever their stance is, they act on their ideals before they let laws get in the way, and sometimes they dare the laws to get in the way. Whether they're portrayed as damn big heroes, too damn idealistic, a Manic Pixie Dream Girl, or just a damn problem depends on the views of the author and, ultimately, readers. Represented in pre-4th Edition D&D by the elf- and fey-like eladrin celestials of Arborea.
Lawful Neutral: The rule-abiding sort. Law and order is more important than whether you're good or evil. Believes in keeping order, though not necessarily in Justice as a universal constant (though they may — this can get complicated). They'll arrest a robber or rapist, but may also kick a family out of their home for failing to pay rent, even if they were poor. May also believe in a Cosmic Order that transcends laws — many monks are Lawful Neutral. Just as often the bad guys as the good guys in an Order Versus Chaos situation. People who think Hobbes Was Right will argue that all societies tend towards Lawful Neutral, as the Always Chaotic Neutral individuals who make up society surrender their freedom to the law in exchange for protection from other Chaotic Neutral individuals. Modrons, D&D beings of geometrically perfect precision and order who inhabit the plane of Mechanus, are Lawful Neutral. Mercenaries who obey their contracts without question, and take either side of the moral spectrum, are Lawful Neutral. The Stoic can make a good Lawful Neutral. Probably the best known example of this alignment is Inspector Javert from Les Misérables (who basically sees "lawful" as the same as "good").
Chaotic Neutral: The ultimate free spirits, or just lunatics? It can go either way. Chaotic Neutral characters are all about freedom, and don't care so much about morality. Sometimes they're just amoral nutjobs, and sometimes they're generally good people with a wild streak that sometimes leads them into bad things. Often used by players in Tabletop Games to excuse doing anything they feel like (in the case of a Game Master who disables evil alignments — see Neutral Evil, below), and often prohibited by the sort of Game Master who also prohibits outright evil characters. Like Lawful Neutral, however, how "good" they ultimately end up seeming depends on which side of Order Versus Chaos the plot tends toward. The toadlike slaad ("I didn't know what he was talking about, so I ate him."), inhabitants of Limbo, are Chaotic Neutral.
Lawful Evil: The ordered sort of Evil, that often ends up in charge. Can be a lot like Lawful Neutral, but nastier. Well-structured, large-scale and often scarily successful evil. May believe in keeping order at all costs, or may simply believe that a well-ordered system is so much easier to exploit. Whether an Obstructive Bureaucrat is Lawful Evil or Lawful Neutral is basically a function of whether he enjoys what he's doing (see above example of kicking the family out of the house). Knight Templars are almost always this alignment. If God Is Evil, he's almost always Lawful Evil. On the "bright" side, the Worthy Opponent and Noble Demon are often Lawful Evil (if they're evil at all), as they tend to develop a "Code of Honor" to guide their actions, and can in fact be dependable allies in an Enemy Mine situation where other alignments might fizzle out. In circumstances where you are not a threat to their intentions, Lawful Evil might well be the "lesser of the three evils", but on the other hand its the one most likely to win and the one that most frequently causes suffering on a grand scale. BBEGs in general tend towards Lawful Evil — mostly since they plan to construct their very own empire that you'd better fall in line with — as do many Magnificent Bastards. A mercenary who always keeps his contract (good or evil), but enjoys a job where he gets to hurt people, is Lawful Evil and more likely to end up working for the bad guys. The baatezu (devils) of D&D rule the plane of Baator with a Lawful Evil fist, and some of these were originally Knight Templar angels. As a good reference point, Big Brother (or O'Brien) from 1984 would be Lawful Evil.
Chaotic Evil: If Chaotic Neutral indicates the truly free spirit, Chaotic Evil is the truly evil free spirit. Whereas the Chaotic Neutral is concerned only with his freedom but isn't a really horrible person, the same can't be said for the Chaotic Evil character. They will do whatever they want to (even if, and sometimes, especially, it hurts other people) and (to them) rules don't matter. Whereas a Neutral Evil character will sometimes follow the law if it is convenient, the Chaotic Evil character occasionally takes pleasure in going out of their way to break the law. So why are they evil? Perhaps they're in it for profit. Maybe they are narcissistic or egotistical. Or maybe they're simply insane; most but not all psychopaths fall under this designation. But contrary to what some believe, Chaotic Evil does not mean the kind of wanton, meaningless slaughter and destruction associated with Stupid Evil. Indeed, it is often the more calculating and intelligent villains of this kind that are the most dangerous. Being Chaotic Evil doesn't mean a character HAS to slaughter an entire village just because he's passing through. Of course, if he's having a bad day, or is bored, he might just jam a knife in somebody For the Evulz. Serial Killers are good examples of Chaotic Evil. It's the canonical alignment of tanar'ri (demons), beings who were created in and by an endless semisentient Abyss that itself is dedicated to entropy, in Dungeons & Dragons. For a great example of how Chaotic Evil can be done well and not be Chaotic Stupid, see the Joker.
It helps to think of it as a 3x3 square with the moral and ethical axes on each side, and all the possible alignments surrounding True Neutral like so:
The alignment any particular character falls under is mostly a matter of opinion in works other than Tabletop Games, where it's usually spelled out (and even then, fans are likely to spill a lot of words about how the creator got the character's alignment wrong). It's also generally only important in Tabletop Games, but that doesn't stop RPG fans from discussing what alignment characters in every other work they like would be — just for fun, try Googling 'Punisher alignment', or better yet, Google Site Search it on an RPG-oriented forum. This is why most of the above statements about which alignment a character "probably" is are qualified (and, incidentally, why none of the examples is The Punisher). There will always be a counter-interpretation.
This is the concept that gives Lawful Stupid, Chaotic Stupid, Stupid Good, Stupid Evil, and Always Chaotic Evil their names. Expect a setting that explicitly uses alignment to make frequent use of Order Versus Chaos and Balance Between Good and Evil type plots. The Karma Meter is a way for video games to represent this. Working out a specific character's alignment is subject to Alternate Character Interpretation, Values Dissonance, and let's not forget mountains of Fan Dumb. Arguments about what the alignments themselves mean often get into the Sliding Scale of Idealism Versus Cynicism.
As the quote for Lawful Stupid, Chaotic Stupid shows, the alignment system was and is meant to be a roleplaying tool (every DnD manual from 2E on mentions this fact). Most players of any TTRPG involving one tend to ignore this, and either ignore their alignment or treat it as a character shackle. This truth in and of itself is the reason so many subtropes (and arguments) based on this concept exist.
If someone is having difficulty depicting a character of a particular alignment because of the alignment, or in imagining how to do so sensibly, it's probably because they're putting the cart before the horse. Alignment isn't personality and doesn't determine it. Personality determines alignment. You should first come up with the personality and see how the character functions based on it, and then see which alignment it fits. For example, instead of presenting Chaotic Evil as doing random evil acts for no reason, you might come up with a character who thinks the only way to get by is to dominate everyone else by using physical violence, and is willing to apply this method at the least provocation, lest he seem "weak", not caring that he hurts others — and then realise his behaviour and attitude amount to a kind of Chaotic Evil, this time with a reason.
A recent meme on a certain imageboard is creating motivational posters of various characters from fiction and real life with a caption explaining their alignment. The ultimate example being a 3x3 grid showing every alignment with varying pictures and captions, but◊ the same subject: Batman.
As with all good concepts, it's very ripe for parody — there are such motivational posters of alignments including "Chaotic Awesome" (for Cartman) and "Chaotic Gorgeous" (Evanna Lynch's portrayal of Luna Lovegood).
This website is also quite helpful in explaining the concept of Character Alignment, and has further info on the nine different alignments.
As a general rule, do not add Character Alignment to any work where it is not featured in canon. The Great Character Alignment Debate explains this in more detail.
See also Unconventional Alignment, Lawful Stupid, Chaotic Stupid, Stupid Good, Stupid Evil, Always Chaotic Evil, Good and Evil for Your Convenience. The Mirror Morality Machine will invert any alignment... except for True Neutral; the opposite of zero is still zero.
Due to the controversial nature of this trope, and not to mention, it's considered shoe-horning to categorize people with these kind of tropes, there will be no real life examples under these circumstances, since it invites an Edit War. Except for outlines of actual Real Life proposed systems (such as the four humors theory).
Examples of Works/Settings With Explicit Character Alignment:Tabletop Games
Dungeons & Dragons: Not only did they come up with the best-known alignment system, but a number of their settings feature gods of different alignments competing for power. Many spells and items will only function on/for characters of a given alignment (moral, ethical, or both). In most settings, a god will accept clerics only of alignments no more than one "step" removed from its own (for example, a Lawful Neutral god, unless otherwise specified, would accept a Lawful Good or Lawful Evil cleric (to complicate matters there is normaly a rule that states that Clerics can only be True Neutral if their god is), but wouldn't accept a Chaotic Neutral cleric), though their lay worshipers can be of any alignment.
In earlier editions of the game, only player characters were able to freely choose their alignment; monsters (that is, any non-human or demihuman creature) were born with their specific alignment and could never change. This was due to the influence of the Outer Planes (which were arranged precisely according to the alignment axis) and the gods of the campaign. A goblin, for example, was born evil, and no amount of counseling would ever change it (though magic might.) The fact all creatures (including PCs) had invisible "alignment auras" that could be "read" was proof of this. The reason for this was, so that good-aligned characters would be justified in killing or stealing from most monsters. There were, however, occasional variations- you might meet the rare non-evil goblin, for example, but it would be the result of crossbreeding, magic, etc.- never willing change.
If the many many conversations on alignment on various boards (oddly only rarely becoming flame wars) are any indication, the rules for alignment are vague. It really doesn't help that the writers don't seem that constant, one iconic character is lawful because they are devoted to something, but another iconic is chaotic because they are devoted to their art.
Planescape introduces intermediate alignments between extremes and classifies them as tendencies. For example, you can have Good-leaning Chaotic Neutral, or a Chaotic-leaning Neutral Good, instead of just Chaotic Good. This seems to make classification of characters who are not exactly in one alignment or another much easier.
Another bit of evidence that suggests that alignment was originally intended to be more "tangible" was the concept of alignment languages. Yes, alignment languages. If you were, say, Lawful Good, then you had the option of learning to speak the official Lawful Good language (tm). Presumably, you were then issued your LG decoder ring and membership card that gave you access to the Lambda Gamma frat house where there is absolutely no underage drinking and a strict curfew. Hey, if you wanted a party house, you should've pledged Chi Epsilon, which has the most bodacious keggers, but you'll probably have trouble getting your roommate to pick up his socks!
Not that the absence of any nonevil Chaotic alignments dials back on the Chaotic Stupid...
And, for that matter, the absence of any non-good Lawful alignments' effects on Lawful Stupid...
D&D's original alignment system was Lawful, Neutral and Chaotic. Lawful generally got equated to good and Chaotic with evil (though the rules and retroclones such as Swords And Wizardry make it clear that this does not have to be the case) but good examples of Chaotics like the unicorn and such may have been the impetus for creating the two-axis system we know and love today.
Chaotic Evil was always the "Kill, Crush, Burn" evil alignment, as opposed to "Whatever benefits me" of the other branches of Evil.
And Lawful Good was similarly distinct from the other branches of Good. Short version: LG had specific prescriptions for "what is Good" built right into it, unlike the others, and was more of a balancing act.
Evil, meanwhile, is more pragmatic and practical. It is the evil of banality, tyranny, slavery — in other words, evil for a specific purpose. An Evil creature will destroy a kingdom to claim its territory for itself or to enslave its populace or any other purpose; a Chaotic Evil creature will destroy a kingdom just because it's a convenient target. This means that Evil creatures typically despise or want to get rid ofChaotic Evil creatures.
Good is, obviously, good; concerned with freedom, liberty, all that other such stuff. They do not specifically associate good with government and are, in fact, very quick to consider toppling corrupt regimes or recognizing when evil is Inherent in the System.
Lawful Good, meanwhile, considers order and good to go hand in hand; a person must be free, but there must also be law and authority, and without a governing force working for the good of others, there cannot truly be good. As the player's guide explains, a Lawful Good character confronted with a corrupt government would much rather infiltrate it and work to bring about reform from inside than topple it and leave the people it rules "defenseless in anarchy".
Unaligned characters, meanwhile, simply don't care about Good or Evil; their focus is on getting on with their daily lives, meaning they can be cruel or kind as they choose, but they don't devote themselves specifically to doing evil deeds or championing good. Your average joe is Unaligned, but so would be a Punch Clock Villain or an adventurer whose motive is purely selfish — a character who only wants to stop the Evil Empire because their home will be levelled if they succeed and doesn't care about anyone else losing their homes, for example.
Both Old World of Darkness and New World of Darkness: Neither have nearly as explicit a system as Dungeons & Dragons, but still has a stat representing how "moral" each character is. This is called by a lot of different names, based on which edition and gameline you're playing, but it's generally a scale of "bestial monstrosity" (0) to "saint." (10) New World of Darkness characters also pick one each of seven virtues and seven vices, which add additional depth. A character who chooses, say, Justice and Wrath will be very different from somebody who chooses Faith and Pride.
d20 Modern, which is built on the same system that Dungeons & Dragons uses, has allegiances. These can be to Ethical (law or chaos) or moral (good or evil) systems, but can also be to other things such as religious beliefs, political views, or organizations. The Urban Arcana campaign setting converts alignment to allegiances for Always Chaotic Evil creatures from D&D.
GURPS Powers allows for "Moral" powers of the types Lawful, Chaotic, Good and Evil.
GURPS Thaumatology also explores the concept of "ethical magic", and offers spells related to such "ethics" such as Good, Evil, Law, Chaos, or even any other concept a GM might add to a campaign setting.
For the most part, however, GURPS as a rule tends to avoid "alignments" as such, and instead represents character traits through the use of Disadvantages.
Warhammer Fantasy Roleplay had five alignments: Lawful, Good, Neutral, Evil and Chaotic. Translating this scale to D&D standards would reveal that when you try to out-good Good, you turn around and approach Lawful Neutral, and similarly, Chaotic is not Evil Plus, but eviler version of Chaotic Neutral. It ties into the setting's primary antagonist being Chaos.
The standard Palladium system of most of its settings, such as Rifts, Palladium, Heroes Unlimited and Robotech has a variation on the alignment system from Dungeons & Dragons. In this system, there are three different types of alignments, broken down into Good, Selfish, and Evil. Palladium rulebooks state that there is no such thing as Neutral, and dismiss the term as misleading (though that doesn't stop them from including a "Taoist" alignment in the Ninjas and Superspies system). Good alignments include Principled, which is roughly equivalent to Lawful Good, and Scrupulous, which is roughly equivalent to Neutral Good. Selfish includes Unprincipled; and Anarchist, which is roughly like Chaotic Neutral . Evil has Miscreant, the selfish but not demonic; Aberrant, who is the Noble Demon as an alignment; and Diabolic, a "cruel, brutal killer who trusts no one and has no value for anyone or anything that gets in his way.". Palladium even includes a helpful list of behaviors associated with their alignments, which helps cut down on arguments on whether or not somebody is acting properly. Scrupulous folk never betray a friend. It says so right in the rule book.
Rifts, and other games by Palladium Books, has seven alignments, broken up into three categories: Good, Selfish, and Evil. The alignments are more or less equivalent to the D&D alignments (with two missing), though it can be a little tricky to figure out which corresponds to which in a couple cases. Principled, which is considered the "highest" of the alignments, is pretty much Lawful Good, and the other good alignment, Scrupulous, is basically Chaotic Good. The two Selfish alignments, Unprincipled and Anarchist, are roughly equivalent to Lawful Neutral and Chaotic Neutral, respectively. The evil alignments are Aberrant, Miscreant, and Diabolic, which align with Lawful Evil, Neutral Evil, and Chaotic Evil. One thing of note is that the guidelines for what each alignment would or would not do is more rigidly spelled out in Palladium Games than most other systems, with each alignment containing a bulleted list. For instance, a Good character would never betray a friend, and neither would an Aberrant Evil character.
FATAL has virtually the same system, only instead of Lawful it's Ethical, and instead of Good it's Moral. So Ethical Moral to Unethical Immoral. Essentially, this being FATAL, it probably comes down to whether you will say "please" and "thank you" when raping someone or not.
Magic: The Gathering has an elaborate alignment system embodied by its Color Pie that fits poorly into good/evil and order/chaos system (as it defines them by a general philosophy). Order and chaos can be included with some stretching: White is devoted to order and Red is devoted to chaos, Blue prefers the control offered by order, Black prefers the unrestricted ambition that chaos promises, Green is strictly neutral either rising above both concepts or thinking too simply to understand either. There is deliberately no color specifically aligned with good or evil. A self centered tyrant would be black, a fascist state is white, a terroristic zealot is red, an uncaring scientist is blue, a Social Darwinist is green.
Once the colors start mixing things become even more complex, combining the parts of each philosophy that mesh. For example:
Red-White characters combine white's love of order with red's frantic energy to create anything from a vicious Knight Templar to a passionate defender of the innocent.
Green-Blue characters can do things as insanely impulsive as creating a deadly plague and as coldly rational as exposing it to a statistically representative sample of the population without ever seeing considering morality.
A non-good example of this is Redcloak, high priest of an evil god who has a plan which will either end with world domination or world destruction. He is a well-developed character with deep personal motivations for his cause, a complex relationship with the lich who killed his brother, and his primary motivation is to change the quality of living for his species (at the expense of any other race).
However, several strips give an excellent illustration of alignments coming into conflict: The Lawful Good Celia, Chaotic Good Haley, and Chaotic Evil Belkar encounter a couple of Lawful Evil Hobgoblins. Belkar stabs the Hobgoblin because he just likes killing. Celia is horrified at his random unlawful murder, but Haley justifies it by saying that as they are fighting a war against evil, the unjust killing was, if not necessary, then at least acceptable. However, then they come into contact with a friendly gnome merchant, who Belkar then also stabs. Haley is horrified, but Belkar points out that the gnome's cart and donkey are of great use to the group, and likely to benefit the resistance more than his hobgoblin slaying. Celia then starts commenting on how Not So Different the situation is, and sarcastically suggests that Haley should paint the corpse to look like a Hobgoblin so that Haley can more easily rationalize this second unlawful killing.
The endless alignment debates over Vaarsuvius's Deal with the Devil in Don't Split the Party. It's gotten to the point where people jokingly start arguing about alignments every time a character moves a muscle.
Is this remark about the jokes about moral justifications morally justified?
Some fans jokingly argue that Belkar could fall within the bounds of Chaotic Good. In this case it's more a bad case of Draco in Leather Pants than ambiguity because, not only has Rich Burlew gone on record multiple times stating that Belkar is canonically Chaotic Evil, Belkar actively revels in it.
The Princess, a Monk, is quite Lawful Neutral. After Calamitus, a Big Bad, charms an innocent audience to attack her, she does not hesitate to knock them all out, contrary to the bad guy's mistaken belief in her being Good.
Madeline the Paladin is quite Lawful Good and veers quickly into Lawful Stupid if she's not intercepted into planning before an encounter.
In the expansion to City of Heroes called Going Rogue, a morality system is implemented which allow a player to move up and down the good/evil spectrum. As well as having Heroes fall from hero to vigilante to villain, a villain can redeem themself and become a rogue, and then a fully-fledged hero. There is also a "grey area" of content for new characters set in a Lawful Evil empire in "Another Dimension'' where being Lawful makes you Evil and being Chaotic bends you to Good.
Every character in the Ogre Battle series has an alignment, ranging from Lawful to Chaotic, which changes based on their actions during battles. (Characters which attack enemies stronger than themselves, for example, grow more lawful, while characters who hunt down and destroy weaker units [or single-handedly defend liberated cities against hordes of weak enemies which the Empire will mercilessly send to their doom] will grow chaotic.) Alignment affects what classes are available to a particular character. Lawful characters tend to have "light" classses (cleric, knight, angel), while chaotic ones tend to have "dark" classes (wizard, dark knight). Just remember Dark Is Not Evil and Light Is Not Good. In addition, there is another measure available only to the main character which goes by multiple names but is generally known as Reputation. The two are completely separate — you can be utterly evil but still be famous and respected for your strength. Many special characters will only join you if your Reputation is high or low enough to suit their tastes, and it affects your ending.
The summoned champions of Fate/stay night each have their own D&D-esque alignment, though the Berserker class is outside it due to lacking rationality. For example, Saber is Lawful Good, Archer is True Neutral, Caster is Neutral Evil while Gilgamesh and Rider are Chaotic Good. However, how accurately each Servant matches their alignment tends to vary wildly: Saber and Caster match their alignments well while Gilgamesh and Rider have baffled fans since their release, leading to many competing theories that try to give a consistent explanation. Most suggestions will only explain one character, though the theory that alignments are carryovers from Prototype that had vastly different character using the same identities has gained some support after more information about it was revealed.
Alignment plays a huge role in the Shin Megami Tensei series of games. Each monster is classed on the Law-Neutral-Chaos axis and the Light-Neutral-Dark axis. The former is the important one: monsters that are Chaotic will refuse to join you if the main character is Lawful and vice-versa. The alignment of the main character is determined by the type of monsters he summons (eg: Lawful creatures will move your alignment towards Law), by his responses to philosophical questions asked at key points of the game and by whose dirty work (The Messians or the Gaians) he carries out. The ending of the game is determined by the final alignment of the main character. Interestingly, Neutrality is presented neither as the uncaring or balancing alignment, but rather one that focuses on individual choice and inner strength, as opposed to relying on outside power.
Megami Tensei I & Megami Tensei II feature alignments along the axis of Good-Neutral-Evil.
Shin Megami Tensei I features an alignment system along the axis of Law-Neutral-Chaos — Light-Neutral-Dark is not actually a Good-Neutral-Evil axis in the traditional sense, instead representing the mythological reputation of the entity in question as something to be revered or reviled; the original manual describes Light as "closer to a god" and Dark as "closer to a demon." It is the earliest known videogame to have an alignment system that directly affects the direction of the storyline and which of the Multiple Endings the player is given, through the choices and actions the player makes that alter the player character's alignment. Shin Megami Tensei II uses the same kind of alignment system. In both cases, the main character's actions on the Order Versus Chaos axis determine the ending, and the game does not take a stand on which path is best.
In Shin Megami Tensei III: Nocturne the previous system of alignment is discarded in favour of three specific philosophies: Shijima (which is closest to Law, except that the Knight Templar tendencies take a different form), Musabi (Neutral, focusing on individuality and freedom of choice) and Yosuga (Chaos with a heavy dose of the elitism that Law was previously known for). Also, there's screwing them all and either returning the world to the way it used to be, or leaving the Vortex World the way it is, and in the Maniax edition, True Demon, in which you say "fuck that noise," give up your leftover humanity and join Lucifer's army in order to take out God and keep this stuff from happening over and over again
Games outside the main continuity tend to ditch the alignment system completely. Devil Survivor, despite having Multiple Endings, bases your ending on who you ally with to gain control of Babel and end the lockdown.
Shin Megami Tensei: Strange Journey incorportaes Law/Neutral/Chaos into battle gameplay: When you or one of your demons hits an enemy with an element they're weak to, other allies of the same alignment will execute a Demon Co-Op attack. Enemies cannot do the same, however, although it's still a good idea to prevent yourself from being pounded with too many weakness attacks.
In short, there are four mayor characters in the series that represent each of the four ends of the axis. Lucifer (Chaos), YHVH (Law), Philemon (Good) and Nyarlathotep (Evil).
A rare action game example, Shadow the Hedgehog works off this system quite well. Using branching story-lines, the player would choose multiple endings using a system of levels made up of three outcomes: hero, neutral and dark. The final levels would involve only two outcomes (neither could be neutral), which would decide the boss fought and ultimately the ending.
Fable I had a Good V Evil system, based on your actions in albion. In Fable II, it was extended to something similar to this trope, with Good/Evil being your morality and Corrupt/Pure being how nice you were to others and your own body. (I.E Pure characters treat their own body as a temple, while corrupt characters would drink a gallon of ale every morning).
Even with the improvements in Fable II, the system is still quite simplistic with the only two discernible options being either Lawful Good or Chaotic Evil. While the game's Big Bad is Lawful Evil, the game does not provide many options to exercise an influence over the story or quests based on one's alignment other than not taking the good or evil quests. The citizens of Albion will still hail you as the greatest hero of all time if you save enough slaves, even if you are also the kingdom's biggest slum lord and adulterer.
Wizardry uses the good/evil axis, though it leaves out order and chaos. The manual states that a good man helps an old lady across the street, a neutral man crosses the street and helps an old lady across, an evil male PC helps a young lady across the street, and the level of evil they all oppose helps an old lady halfway across the street. A note adds that since the game uses Purely Aesthetic Gender, a good woman helps an old man across the street.
Dwarf Fortress rates regions of land on a "benign-neutral-savage" and a "good-neutral-evil" axis. So, benign good is "serene", while savage evil is "terrifying". (It's...not very good for your dwarves to start in an evil area. Really. For them, at least.)
Additionally, the main difference between savage-evil biomes and savage-good biomes often comes down to little more than whether your dwarves get massacred by rampaging zombies, or by rampaging unicorns.
In Age of Wonders, the races are aligned on the Good-Evil spectrum, with Pure Evil (The Undead), Evil (Dark Elves, Orcs and Goblins), Neutral (Human, Azracs, Lizardmen, Frostlings), Good (Elves, Dwarfs, Halflings), and Pure Good (Highmen)
Battle for Wesnoth has the alignments of "Lawful", "Neutral", and "Chaotic". Alignment is decided by class and cannot be changed. It also only affects one thing: how well units fight during certain times of day. "Lawful" characters fight well at day and badly at night, while "Chaotic" characters are the exact opposite. "Neutral" characters are never affected by the time of day. Caves function as a permanent night, and characters with the Illumination skill cause the day/night cycle to act one stage closer to day (night is like dawn/dusk and dawn/dusk are like day).
The Fallout series goes with a Karma system. It really is only one scale, and doesn't involve the lawful-chaotic scale, only ranging from good to evil. The main relation to the D&D alignment system comes from how the player chooses to gain points in either direction. It is generally easier to become good than evil by killing lots and lots of people for the hell of it, ironically, since many of the karma inducing characters you can kill easily in the games are evil aligned. While it is possible to be dog-kickingChaotic Evil by going into a town and killing guards and civilians, you will most likely alert several higher leveled guards while doing it, while doing the Lawful Evil approach and subtly plan genocide by detonating live atomic bombs and unleashing mass-killing viruses in the water will comfortably put you on the evil side of the scale without having to shoot a single guard doing it. The good side of the scale tends to be a little more flexible however, allowing you to both be a trigger-happy nutjob and an agent of various good organizations around while doing it.
ADOM has the old-D&D-style "Order Versus Chaos (psst, it's really Good vs. Evil)" system. There's a scale of symbols representing the different steps from completely Chaotic to completely Lawful:
C- C C+ CN NC N- N= N+ NL LN L L+
Whether you're primarily Chaotic, Neutral or Lawful (as indicated by the first letter of your alignment) determines which of your three racial deities you serve. You can pray to become a champion of your alignment after having the most extreme version (which for Neutral, could also be called the least extreme) and getting extremely favoured by your deity.
The sequel, JADE, is supposed to add the Good/Evil axis to this.
NetHack has D&D-inspired Order Versus Chaos alignment system which decides what artifacts you can use, what deities you worship and if you get punished for things like stealing from shops or attacking peaceful creatures. The UnfoughtBig Bad evil god Moloch is unaligned
Mortal Kombat tended to keep to a dichotomy of good vs evil for the most part, but the Order Versus Chaos element is also heavily played and hard to ignore. For one thing, the first game made reference to Shang Tsung corrupting the shaolin tournament and the furies, shifting the side of the tournament's order allignment to the chaos allignment. Later on we see Shang Tsung's boss, the Emperer of Outworld, Shao Kahn, who uses his extermination squads to invade and merge other realms using brute, compassionate-free, aggressive force, all while completley ignoring and defying the rules and regulations the Elder Gods commanded to stop this happening. Later on, in the 6th installment Mortal Kombat Deception, we are presented with the former ruler of Outworld, Onaga the Dragon King. Who still wants to merge the realms much like Shao Kahn, but do so by merging the special kamidogu instead, which would combine the realms automatically, creating complete stability, without the need for violent conquest.
This is the game where the Order Versus Chaos dichotomy comes into play. With only a handful of 'good' characters left, either killed, or brainwashed to serve as Onaga's pawns, we're left with previously (and new) 'evil' or grey characters teaming up and binding together to fight on the side of chaos to fight for freedom that's threatened by the side of order. Suddenly it's no longer about good vs evil. New realms introduced in the series include Chaosrealm and Orderrealm. Introduced characters that maintain morally grey and/or take no stances on good and evil, are a guardsman from the Orderrealm outright stated to want to preserve law and order at all costs, a cleric from the Chaosrealm with a desire to see the world descend into turmoil with militant obsession to oppose any control (good or bad), a resistence revolutionary from Orderrealm taking a leaf out of the chaos book to fight for freedom in Orderrealm and oppose all regulations and laws, and your standard Wild Card mercenary that takes no sides in the whole ordeal (good, evil, order or chaos). If order wins, the universe will be destroyed. If chaos wins, you can celebrate for about a minute before you realize you helped your former evil return. You're screwed either way.
The Class Of Heroes series utilizes the moral axis of (Good, Neutral and Evil) to influence whichever class is available to a character. All ten playable races can cover the entire axis — including the demonic Diaboloses or the angelic Celestians, thus it's not impossible to create a good Diabolos or an evil Celestian.
Professional Wrestling has a bit of an implied alignment system, with all wrestlers being divided into Face, Heel, or Tweener, though this generally isn't acknowledged in Kayfabe — except in Mexican lucha libre promotions, and lucha-inspired promotions like CHIKARA, where wrestlers are openly referred to as either "Tecnicos" or "Rudos". Look for media based on North American wrestling, such as video games, to use euphemisms to refer to this system (such as "Fan Favorite" for Face and "Rule Breaker" for Heel).
When a D20 game was released under WWE's licensing, the alignments were actually Face, Tweener, and Heel. The most recent games have 'Clean' and 'Dirty'; apparently no real 'tweeners.
That's because Tweeners can't get a crowd reaction in today's WWE anymore, probably being considered indecisive as to which side they would be taking. You either do something to make them CHEER you (making you Face, even if your alignment says otherwise) or to make them BOO you (which would make you Heel...even if you're John Cena). The independent companies have more leeway with this system, and some of the most popular non-WWE wrestlers in the US are firmly in Tweener territory; just look at Christopher Daniels.
Adventure Time has mentioned the idea of Character Alignment on occasion, such as the unaligned ant from "The Enchiridion!" and Hunson Abadeer from "It Came From the Nightosphere" and "Return to the Nightosphere". Near the end of "Ignition Point", Finn and the Flame King even use D&D terminology to discuss the alignment of the flame people and Flame Princess.
The D&D 3rd edition sourcebook Complete Scoundrel (which includes options and prestige classes for playing a Trickster Archetype or Guile Hero) lists several characters as examples of "scoundrels" of different alignments.