In the mid-'90s, Hal Jordan became a supervillain called "Parallax" due to witnessing the destruction of his hometown, Coast City. After Parallax obliterated the entire Green Lantern Corps, a single new replacement was chosen in geeky graphic artist Kyle Rayner, who brought in a whole new generation of readers with his nerd-chic attitude and more imaginative use of his Green Lantern powers. Unfortunately, the new status quo overrode the old supporting cast, driving a wedge between Hal Jordan fans and Kyle Rayner fans.
In the mid-2000s, DC Comics would return Hal Jordan to his former glory, by explaining that "Parallax" was actually the name of an imprisoned cosmic parasite that fed on fear and corrupted Jordan through his Power Ring. Furthermore, Parallax was blamed as the source of Green Lantern's infamous weakness towards yellow, by revealing that emotions of fear are attuned to the color yellow, as per a pseudo-mystical "emotional color spectrum" shared by all living creatures, with "green" attuned to the neutral emotion of "willpower". Later developments would merge the Jordan and Rayner eras, have the Guardians descend further into Knight Templar-hood, and introduce the rest of the spectrum and their corresponding Lantern Corps, such as Agent Orange or the Sinestro Corps.
The franchise is currently helmed by Geoff Johns, who spearheaded Jordan's return and developed the emotional spectrum. It currently consists of:
Green Lantern (written by Johns), starring Hal Jordan and Sinestro, who was re-inducted into the Green Lanterns against everyone's wishes. Although Hal had been expelled from the Corps, Sinestro has recruited him as a sidekick for non-Guardian-sponsored missions - including going against the Guardians themselves. Currently a new recruit, Simon Baz, headlines the book, as Hal and Sinestro are presumed dead - they're still out there somewhere, but their storyline has become the B-plot.
Green Lantern Corps (by Peter Tomasi), starring John Stewart and Guy Gardner and focusing on traditional space adventures.
Green Lantern: New Guardians (by Tony Bedard), starring Kyle Rayner on the run from the GLC as he leads a team drawn from all seven corps.
A.I. Is a Crapshoot: Before forming the Green Lanterns, the Guardians tried a lil' automated help with the android Manhunters, who were so good at their job... they annihilated all life in Sector 666. After dispossessing the Manhunters, the Guardians proved they never learn by creating the cyborg Alpha Lanterns.
During "War of the Green Lanterns" it is revealed that the Manhunters didn't go bad at all, but were reprogrammed by Krona to commit the massacre.
The Alpha Lanterns are a bit of a subversion. They never turn evil of their own volition, so far it's only been when under the control of an outside force (such as Cyborg Superman or Krona).
All Your Colors Combined: The ultimate objective of Blackest Night is to get all seven corps of the light of the emotion spectrum together to find their source and get the white light of creation recreated to finish off the Black Lantern Corps.
Ancient Astronauts: Earth's very first Green Lantern, a Chinese man named Jong Li, received his Power Ring during the Qin Dynasty (between 221 and 206 BC). Being a Chinese peasant living before the birth of Christ, Jong Li naturally thought the ring was a gift from the gods and his mission as a divine command.
Angry Black Man: Bronze Age John Stewart. He cooled off thanks to later writers, becoming more contemplative, but he still has his moments.
Anthropomorphic Personification: Each of the seven shades associated with the Emotional Color Spectrum gets a physical manifestation of its power, which usually requires a sentient host to "bond" with. Parallax was this for fear (and the color yellow), and there's now one for every color, including Ion the Space Whale for the Green Lanterns.
On a broader note, all emotions are represented by the crystal-white "Entity" that allegedly seeded life throughout the universe, until hibernating in Earth. In practice, Nekron acts as its opposite number, despite christening Black Hand as the personification of Death.
The Antichrist: It has been shown that since an early age, Black Hand had an unnatural obsession with the dead, and was long destined to provide the "door" for the Black to enter our world. He just had to blow his own brains out and start licking Bruce Wayne's skull to do it.
Art Attacker: The Tattooed Man has the power to bring his tattoos to life.
Asshole Victim: Sure, the Sinestro Corps' invasion of Daxam in order to enslave the inhabitants is beyond reprehensible... then again, the Daxamites are violently xenophobic assholes with an intense hatred for pretty much anything not them, which makes feeling any sympathy for them quite a difficult task.
Back from the Dead: Hal Jordan's timely resurrection during the climax of Rebirth, thanks in no part to the Guardians preserving his corpse. Blackest Night serves as a huge lampshading and deconstruction of the whole thing.
Badass Creed: All the Green Lanterns, as well as the various other corps that have spun off from them.
Alan Scott has his own, albeit less memorable:
And I shall cast my light over dark evil For the dark things cannot stand the light The light of the Green Lantern!
This version was originally given to Tomar-Re as a Mythology Gag.
Berserk Button: Don't try to pry into Larfleeze's past. It won't end well. And don't even think about either mentioning Mongul's name in front of Arkillo.
The Berserker: The entire Red Lantern Corps, save their leader Atrocitus, who can at least socialize (to an extent).
And now, in the Red Lantern series of the DCU reboot, he's trying to get a lieutenant, saving at least one more corpsman from this trope.
Beyond the Impossible: The Guardians made sure that it would be physically impossible for a lantern to kill one of them. When Hal Jordan kills Krona they are shocked and afraid.
Bizarre Alien Biology: Truckloads of it. Most of the second-fiddle Lanterns (not limited to the Green Corps) aren't remotely humanoid (even if it's just from the neck down), except maybe for the communication capabilities. For example, Bzzd is a sentient fly-like Green Lantern, while Sinestro Corps member Slushh is pretty much a human-sized amoeba with bones scattered inside of it.
Brainwashed and Crazy: A disturbing number of Green Lanterns have fallen victim to this trope at some point.
Anyone possessed by an emotional entity tend to follow the emotion in charge rather than their own logic. Parallax in particular loves turning decent people into terrorizing monsters.
Breaking the Fourth Wall: John Stewart, throughout the "Mosaic" series. He's constantly addressing the reader, and once even notices that he's been drawn by a fill-in artist.
John Stewart: ''Why do I suddenly look so different?"
Break the Badass: Kyle Rayner once related to Green Arrow how Guy Gardner (a Green Lantern notable for not just being able to "overcome" great fear, but being honest-to-God fearless) used to tell funny stories about some of the truly ridiculous villains Hal Jordan used to fight. But, Rayner notes, "Guy never told any funny stories about Sinestro", the one villain who ever scared the crap out of Gardner.
Cats Are Mean: Red Lantern Dex-Starr, who's a blue housecat, and like all of his Red Lantern fellas is full to the brim of murderous rage and red-hot plasma that annihilates everything it touches.
The Cavalry: Sometimes things get too bad for one Lantern to handle. When they do, a call for help is made, and just in the nick of time any number of bright green dots will appear in the sky. It makes sense; they're effectively cops, so they would call for backup from time to time.
Taken to extremes in "Blackest Night," where cavalries were called in from several whole Corps.
Character Shilling: Widespread shilling for Kyle Rayner appeared when he replaced Hal Jordan.
Chekhov's Boomerang: Sodam Yat was officially created by Alan Moore as part of a prophecy detailing the end of the Corps. It took around twenty-five years for him to make his official comic book debut. Mogo got a similar deal.
The Chooser of The One: The Rings individually seek those who can overcome great fear, and Mogo helps them determine moral individuals.
Kyle Rayner attempted some form of this during his time as Green Lantern, except EVERYONE close to him figured it out in record time. A tiny little domino mask like that really isn't much of a disguise, you know! Guy Gardner and John Stewart don't even bother.
This happened to Kyle AGAIN in the first issue of Green Lantern: New Guardians, where rings from every Corps identified him by name in front of a crowd of people.
Close On Title: Every issue of the John Stewart-centric Green Lantern: Mosaic has the story title on the last page.
Cold Sniper: Sinestro Corps member Bedovian, who can snipe targets from three Space Sectors away.
Green Lantern John Stewart can become this, when needed.
Black = Death... or the vampiric absence of any emotion.
White = Life... the overwhelming extreme of all emotions.
Comically Missing the Point: When Saint Walker asks that he not be treated as special by the Blue Lantern recruits just because he was the first, they start talking about how even his humility sets him apart.
Conservation of Ninjutsu: One Green Lantern is powerful enough to pacify Superman, but all four of Earth's Lanterns together are a lot weaker than they should be (though still not easy to beat). The Green Lantern Corps as a whole, however, get their butts handed to them on a weekly basis, often leaving the last remaining Lantern to save everyone else.
Subverted in the Sinestro Corps War, where the Green Lantern Corps get utterly trounced, until the Guardians revoke the "no-kill" policy.
Played straight with the Manhunters, who have no problem crippling a single Lantern like Hal, but are destroyed in droves if they ever fight a GL in packs.
While not generally invoked in the comics, this could actually be justified by the fact that the Lanterns all draw their power from the same source. It would actually make sense if the fewer Lanterns there were, the more powerful they became, and in fact the fewer members a Corps has, the more powerful they seem to be individually, down to Larfleeze who is literally a one-man Corps.
In fact, this is literally true in the case of the Orange light which Lex Luthor stated is most effectively wielded by one person.
Crouching Moron, Hidden Badass: Larfleeze is quite possibly one of the more goofier characters in the books, and while the other Corps all agree with this to a fault, they also realize that when his greed kicks in, it is not a pretty thing to deal with.
Dark Is Not Evil: The modern take on Sinestro explores this, as far as him wanting to instill "order" throughout the universe as the motive for his villainy, which often plays out like an Evil Plan.
Technically, the Black Lanterns fulfill this as well. As evil as they appear, there is no intelligent malevolence in their motives. Nekron is beyond good and evil, and just wants to end all life because it's trespassing on his territory.
John Stewart is NOT dating Fatality, despite her borderline obsession with all things John Stewart; even BEFORE she was in the Star Sapphire Corps and still out to kill him she had no problem with stripping near/completely nude and grinding against his lap... while he HAD a girlfriend!
Death Is Cheap: Deconstructed in Blackest Night. It turns out it was Nekron all along that has been allowing heroes to return from the dead, which effectively makes them sleeper agents for his cause.
But Hal one-ups his claim by affirming that, while Nekron did allow them another shot at living, it was him and his resurrected friends - like Superman and Green Arrow - who decided to accept a second chance, meaning they could as well refuse to come back and stay dead.
That, and there are numerous other characters who died in some way but came back, and Nekron has yet to take credit for those resurrections. Most of the characters whom he claims responsibility for, such as Superman, Wonder Woman, and Green Arrow, are just the most well known cases.
Death Seeker: The Cyborg Superman was an astronaut named Hank Henshaw, whose consciousness was bonded with technology after a deep space catastrophe. Now, all he wants from life is for it to put him out of his misery.
Guy Gardner is singled out by the Oans to be Lantern #1 of the Honor Guard for this reason. He's not the most imaginative, not the most heroic, and definitely not the brightest, but he has no fear whatsoever.
Earth Is the Center of the Universe: Actually, Oa is the center of the universe, but Earth is the center of the multiverse and would trigger the end of all reality if it fell. As of Blackest Night, our little backwater planet is the vacation home of the Entity that created all life.
Earth is also considered the most diverse planet in the universe, for some reason, with more variety in flora and fauna than most entire solar systems. May be hanging a lampshade on the fact that most alien worlds in the DCU are a Single-Biome PlanetOf Hats.
Sinestro (with Sector 3600) destroys the rebuilt Bolovax Vik (Kilowog's home planet), along with the spirits of Kilowog's race
John Stewart's failure to save Xanshi in Cosmic Odyssey.
Kyle Rayner destroying Oa during his fight with Parallax.
And now, during War of the Green Lanterns, John kills Mogo, the sentient planet, in order to stop Krona from using him to recruit any more mindless soldiers to his army.
Eldritch Abomination: Subverted. All of the emotional personifications like Parallax and Ion very well seem to be creatures beyond mortal comprehension, except they're all really the ascendant forms of the first organisms to ever "feel" their respective emotions. Parallax really was a locust-like bug once, Ion was some kind of primordial fish, etc.
Played straight with the Entity and Nekron, who are the seed of all life, and the void between it.
Elemental Rock-Paper-Scissors: Sort of. Each of the rings seen has different powers, and interacts with other rings in different ways. For example, Orange can absorb Green constructs but not Violet or Blue. Blue supercharges Green and nullifies Red, but is close to useless on its own. Yellow is devastating to a Green Lantern that hasn't figured out how to overcome fear, and so forth and so on.
Enemy Mine: You will get a migraine from trying to keep up with the number of villains that have teamed up with the Green Lantern Corps over the years, either to stop a greater evil, or just because it made more sense to have them as a partner at that time than an enemy.
Since Blackest Night, this has almost become the status quo. First all the corps came together to fight off the Black Lanterns, then Sinestro's put back on the Green Corps and goes to Hal Jordan for help, plus there's the "New Guardians" team...
The Green Lantern archetype has also had an Evil Counterpart from another universe named Power Ring.
The Black Lanterns are the Evil Counterpart of ALL the other corps.
Kyle's first evil counterpart was Effigy, a troubled youth who used the fire powers given him by the Controllers for his own pleasure. Writer Ron Marz said he was intended to be Kyle's "Sinestro" but not just "The guy with the yellow ring"... which Nero ended up being!
Eye Scream: Kyle Rayner freaking LOVES this trope. During his first fight with Major Force he had no problem gouging out his eye with a thumb. When depowered and fighting a Cthulhuian horror, he slammed a sharpened bone into its eye. When he fought Major Force again he picked up a shard of glass and gouged his eye out AGAIN! When Parallax taunted him inside his own mind, he picked up a pencil and gouged out its eye. In a fight with Kyle Rayner he will go for the eyes.
Ironically, Batman's plan against him should Kyle go rogue is to blind him. If Kyle can't see, he can't properly "draw" constructs.
Genius Bruiser: Even without his ring, Kilowog is both superstrong and a technological genius.
Flanderization: The Guardian's hypocrisy, intolerance of emotion, and total inability to make good decisions have been greatly exaggerated in recent years. There is a reason they lasted billions of years without collapsing on themselves, you know.
Glorious Mother Russia: Kilowog helped create the Rocket Red Brigade for the Soviet Union, due to his then-interest in Communism.
God for a Day: When Green Lantern Kyle Rayner became Ion, a being with all the power of the entire Green Lantern Corps, he tried to use his new might to feed starving children in Africa, heal his friend's back-injury, restore his girlfriend Jade's powers, etc, until Superman advices him to back down because people around the world have started to worship him as a god. Soon after he sacrifices the power so that the Guardians of the Universe and the Corps can live again.
Also Hal Jordan as Parallax tried to use his godlike power to destroy and remake the universe.
Handsome Lech: Hal Jordan, at his worst. Guy Gardner, though mostly in his own mind.
Heel Face Brainwashing: The Indigo Tribe can take individuals of dubious morality and turn them into peace-loving hippies, whether they want to be or not. This includes themselves.
Heroic Willpower: All Green Lanterns have this, as their rings are quite literally empowered by it.
Holy Halo: Green energy shields, at that. Occasionally, the GL insignia on each member's chest will project a holographic logo, which is meant to emulate the police sirens during a chase.
Home Field Advantage: The living planet Mogo is a planet sized Home Field Advantage. At least, while it was still alive.
How Do I Shot Web?: The Corps has training facilities that are optional in the older stories and mandatory for the modern ones.
Human Alien: Green Lanterns Sodam Yat (from Daxam) and Zale (from Bellatrix) look exactly like a Caucasian and African human respectively. Fatality (currently of the Star Sapphires, from Xanshi) also looks like an African human.
...and four cycles later, in the recreation complex, Katma Tui realized that for the first time in many years' service, she had heard a Guardian make a joke. She felt vaguely uneasy for the rest of that day.
Iconic Logo: It's varied from person to person over the years, but the one used by the Corps itself is the best known.
Ignorant of Their Own Ignorance: Larfleeze of the Orange Lantern Corps was this, locked away in his own filthy paradise in Sector Vega for eons until the Guardians and Lanterns came a'knockin'. Now free to roam the cosmos, Larfleeze is too in love with his self-indulgence to realize he could probably take down every Lantern Corps by himself.
“It is believed that the Rattle Watchmen, who patrolled New Amsterdam in the 1650′s, carried lanterns at night with green glass sides in them as a means of identification. When the Watchmen returned to the watch house after patrol, they hung their lantern on a hook by the front door to show people seeking the watchman that he was in the watch house. Today, green lights are hung outside the entrances of police precincts as a symbol that the ‘Watch’ is present and vigilant.”
Internal Affairs: The Alpha Lanterns, cyborg investigators who mirror the tactics and perspective of the Manhunters a bit too much.
Invocation: Green Lantern oaths, which are traditionally said when charging Rings from a Power Battery.
It's Been Done: In-universe, the Controllers and the Zamarons have tried their hand at making knock offs of the Green Lantern Corps. The Zamarons have been more successful with the Star Sapphires then the Controllers have been with any of their attempts. In fact, most of them were killed when they tried to make a Lantern Corps using the Orange Power Battery, promptly being torn apart by Larfleeze's Orange Lanterns the moment they tried to take it.
It goes deeper than that. The other GLs, when they lose their rings, get all mopey and feel useless. Gardner, when he lost his ring, went out and stole a yellow one from the vault of the Oans (a ring that could only be recharged by fighting other Green Lanterns), which got him his own ongoing, then when he broke that ring fighting Parallax, he unleashed his hidden alien DNA to become Warrior, then briefly joined the Corps' secret black-ops squad, and eventually got a new green ring. Gardner doesn't just jump, he knows where The Call lives and he willhunt it down.
Hal Jordan in issue 4 of "The Road Back". He's spent the previous three and a half issues wandering around, taking odd jobs and trying to find some purpose in life in the absence of the Green Lantern Corps, which didn't exist at the time. When he finds out that an insane Guardian is taking cities from all over the universe and relocating them to Oa, he mans up, recites the GL Oath, and heads out into space to deal with the problem.
Kick the Dog: Though he is being portrayed more sympathetically, Sinestro does occasionally do this to remind readers that while he might be justified in questioning the Guardians' authority, he is still a villain. He killed Red Lantern Laira just when it seemed like Hal might have calmed her down and taunted Hal about it and then he later stabbed Ganthet.
Kryptonite Factor: Infamously, the color yellow. This was later retconned to be caused by Parallax, a cosmic entity that embodies fear, which in turn is locked to the color yellow. Eons ago, the Guardians trapped Parallax within the Central Power Battery that fed all Power Batteries and Power Rings in the GLC. Over time, the entity was able to exert enough influence to cripple any Green Lanterns in contact with its favorite hue. Currently, Green Lanterns still have trouble with yellow objects, but it's no longer impossible to affect, just more difficult.
Since that discrepancy has been taken care of, each Lantern Corps have inherited a weakness against some other color of emotion. For example, Blue Lanterns have the only rings capable of quenching the flaming blood of the Red Lanterns, Green Lantern rings suck against Sinstro's custom yellow rings, and Indigo Lanterns can use any other color against its user.
Last of His Kind: Kilowog is the last survivor of his race after his home planet, Bolovax Vik, was destroyed during the Crisis. However, it was briefly restored by Kilowog, only for Sinestro to destroy it once again. Currently, the remnants of the race exist within Kilowog's psyche due to Kilowog's Bizarre Alien Biology, but can only really communicate with them while he is on Mogo.
Fatality is the last survivor of Xanshi, which John Stewart kinda-sorta helped to destroy.
Finally, Kyle for awhile was the last remaining Green Lantern and Ganthet was the last Guardian.
And according to the modern take on the Legion of Super-Heroes, Sodam Yat will be the last Green Lantern in the 31st Century.
Light Is Not Good: Played straight with the Red Lantern Corps, Agent Orange, and the Sinestro Corps, who are all part of the light of the emotional spectrum.
Almost none of the Corps are straight-up good guys. The Green Light is held by the Guardians, who have a reputation of causing as many problems as they solve. The Star Sapphires are getting better, but have a history of Love Makes You Crazy. The Indigo Tribe is believed to be largely made up of sociopaths who have to have emotions forced on them by the Indigo Light (and even if they're not they're creepily detached anyway). Only the Blue Lanterns haven't made any dick moves so far, but they're also shown to be utterly ineffectual without piggybacking on another light.
Good Is Not Nice: Even the Entity, the embodiment of life itself, isn't morally conventional, given the fact that part of its plans to preserve life, it revived powerful villains and tasked one of them with a murder and another with an assault. It's also become clear that for some of the revived heroes, the second chance given to them is by necessity not a gift but a loan.
Love Cannot Overcome: Hal Jordan and Carol Ferris have done this to each other repeatedly over the years, since his identity as Green Lantern and hers as the domineering, villainous Star Sapphire frequently complicate their underlying mutual love.
Love Makes You Crazy: The de facto trouble with the Star Sapphire and its Corps. The Star Sapphire itself is a symbiotic crystal that bonds with women in desire, at the cost of making them psychotic. Things got a bit better when the Zamarons started filtering the violet light of love through Power Rings, except now there's the Predator, the emotional entity of love, whose nature, despite the name, is actually somewhat benevolent. According to Carol it's the host that makes the Predator's love evil not the other way around.
Loyal Phlebotinum: Power rings will choose their successors when their wielder dies. Though more recently it has been revealed that Mogo actually helps direct this process.
Hal Jordan is one of the notable exceptions. Abin Sur actually triggered the search mechanism as he was dying and had a chance to introduce himself to Hal.
Kyle Rayner managed to be a total exception to this rule, as his selection for being a ring bearer was totally random, and a simple case of being in the right place at the right time. Not that it mattered.
Luke, I Am Your Father: Green Lantern Corps reveals that Soranik Natu's father is Sinestro. Apparently, Natu's mother thought that being the daughter of their planet's dictator would screw her up, so she was put up for adoption.
Magic Meteor: Hector Hammond found meteor rocks and used their powers for evil.
Metaphysical Fuel: Lantern rings draw their power from the emotions of all life in the universe.
Military Superhero: Both Hal Jordan and John Stewart are former military, but except for his DC The New Frontier incarnation, it's not a big aspect of Hal's background. John, however, is VERY much this trope. He's a retired Marine, and you better not forget it.
Mind Rape: Done to Ganthet by the other Guardians after War of the Green Lanterns to rid him of his emotions & personality.
Misplaced Retribution: One story's antagonist is the Aerialist, who's under the delusion that someone at Ferris Aircraft murdered his beloved (the death was in fact a freak accident) and therefore seeks revenge against the company. It's notable for being one of the few times Hal Jordan thought the Insanity Defense would actually work, even citing the M'Naughten guideline.
Missed the Call: Guy Gardner, initially. As revealed in Booster Gold, it is revealed to have been due to Booster and his time traveling. Who knew?
Most Common Super Power: If you're a humanoid female of any alien race, and have the option to join the illustrious Green Lantern Corps, you will have these. It's practically a minimum job requirement.
Must Make Amends: In The DCU, we had Hal Jordan completely lose his sanity and decide to fix his failure to save Coast City... by killing the Green Lantern Corps (They came back), killing Sinestro (He came back), and then killing the universe (it came back)... so he could remake reality "right". Fittingly, after all this nonsense, he got better and went on to try and make all of that right, and ended up sacrificing himself to save the world (of course, he came back). Then a few years later, Geoff Johns retconned the whole thing to Jordan being possessed by a killer space bug made out of fear, but...
My Significance Sense Is Tingling: Happened to Guy Gardner in the Emerald Fallout arc in Guy Gardner: Warrior, when he sees a vision of Oa's destruction, and Hal killing Sinestro, after his yellow Power Ring begins to malfunction.
Also, Jack T. Chance, whom Hal describes as "being reprimanded more than Guy Gardner".
Non-Mammal Mammaries: Occurs with a considerable frequency and in many alien races. Particularly notable in the case of the Guardians and the Zamarons. Both are descended from the Maltusian race, which may have been the first sentient organic race in the universe. The Guardians were originally the males of the race, and the Zamarons the females (although this has since been retconned somewhat). The two split up billions of years ago. In that time, both have individually diverged physically. The Guardians, who pretty much fly at all times, have become small and possess very short legs, much as one would expect. But the Zamarons, who have not borne any children in aeons, still have fairly impressive cleavage. This is all the more striking when one considers that the new female Guardians are barely distinguishable from the males.
Although recently it's been revealed that current forms of the Guardians aren't natural for them at all, but rather a result of some wierd process that makes them ultra-powerful midgets. Most exemplified by Krona, who was tall and buff mere years ago, but now has evolved himself into a Guardian form. If the Zamarons did the same, they would probably look like the female Guardians.
Noodle Implements: The Controllers have been cited as responsible for the creation of the Darkstars, but also the invention of the Beta Men and the Effigy Platoon, which seem to be knockoffs of the Omega Men and another knock off of the Green Lantern Corps specifically.
Non Uniform Uniform: Members of the Green Lantern Corps are allowed to customize their uniform pretty much however they choose so long as they keep the green-black-white color scheme and the Lantern badge is clearly visible.
Obviously Evil: C'mon, he's named Sinestro and has a Snidely Whiplash mustache.
The leader of the Red Lanterns is called Atrocitus. As in atrocity.
Odd Couple: A number of the Lantern partnerships. From Vath and Isamot, originally hailing from opposite sides in a war, to Mogo, a planet, and his partner Bzzd, a tiny fly-like insect.
One Gender Race: The Zamarons and the Guardians could be considered this. They're really from the same race, the Maltusians, with the Zamarons being the females who decided to defend and fight for love and the Guardians being the males who decided to maintain order, but they live in totally separate societies and don't interact unless it's to butt heads. Kyle Rayner, when resurrecting the Guardians, chose to make half of them female in the process, and they've been that way in the comics since (although Geoff Johns retconned it so the Guardians were always half-female).
On a lesser level, the Star Sapphires, started by the Zamarons, only have female members. Geoff Johns says men can join, "but most are not worthy."
At one point things got so bad for the Green Lantern Corps that the last Guardian teleported to Earth and threw a ring at a random person. Eventually they got better.
This happens to the Corps every so often. When Hal Jordan was still a rookie, the villain Legion had defeated the entire corps with its gigantic yellow suit of armor, but Hal figures out that if he covers Legion in mud, his ring will work on him. When cracking the armor open turns out not to have been the best idea, Hal flies into the central power battery and supercharges his ring, giving him the strength to defeat the villain on his own.
After the Crisis on Infinite Earths, the GLC is reduced to the three Lanterns of Earth and a small handful of others spread around the universe. When the sole remaining Guardian is driven mad by solitude, it's pretty much up to Hal to save the day again.
Nova Corps: After a devastating interstellar war, the superpowers of a million-man-strong force were co-opted into one super suit, leading to several Heroic RROD situations.
In First Flight Sinestro has destroyed Green Lantern battery, all of the remaining Green Lanterns are left powerless. Only Hal was able to get green elements power working again and fight Sinestro one on one.
Only Sane Man: Among the Guardians it's Ganthet and then his lover Sayd, the only ones to value emotions and not ignore an "end of existence" prophecy.
Passion Is Evil: The coda of the Guaridans. The Green Light is the center of the spectrum and the most stoic. The other lights are further from the spectrum (with red and violet being the extremes). Red Lanterns and Star Sapphires represent Rage and Love, specifically, and since their colors are on the far ends, their emotions control them. The more powerful the emotion, the more it controls the Lantern. A frequent theme in the mythos, especially when the Guardians became despotic and started condemning emotions and the other Lantern Corps turned up as Foils.
Phlebotinum Battery: A Green Lantern ring is charged by a lantern connected to the central battery on Oa. The ring has a limited power life span and they have to recharge it every so often (the exact time changes based on the continuity).
Plot-Relevant Age-Up: In a 1987 issue of Green Lantern Corps, Arisia subconsciously uses her Power Ring to age herself to adulthood to get Hal to like her, due to her crush on him.
Rogue Drone: Scar, the rogue member of the Guardians. A physical disfiguration — a scar on her face by an enemy — is what triggers her deviation from the rest of her race. Dying and becoming an undead will do that to you.
Save the Villain: Blue Lantern Saint Walker is introduced by him telling Hal Jordan that they need to save Sinestro, who is either going to be executed by the Green Lanterns or murdered by the Red Lanterns.
Shell-Shocked Veteran: The Green Lantern Vath Sarn seems to show some signs of PTSD, more-so than his partner, and fellow veteran from the Rann-Thanagar War, Isamot Kol.
Vath discovered his greatest fear through Mother Mercy: the planet Rann without war or strife, rendering soldiers like Vath redundant. He was drawn holding a gun to his head, about to kill himself because he felt he had no other use.
Shout Out: Kyle Rayner once created Gurren with his Power Ring in Countdown To Final Crisis◊. He also created a Patlabor in Sinestro Corps War.
And in The 2011 movie, Hal actually makes a drill and literally drills through Parallax, the physical embodiment of fear/despair, all the way to space/THE HEAVENS! That Shout Out pretty much summed up the entire second season of Gurren Lagaan.
During Kyle's tenure on the Green Lantern series, a lot of his constructions were shout outs to Anime, video games, and cartoons. He enjoyed making Mecha and on at least one occasion he made a Chun LiExpy.
Split Personality: Carol Ferris (has since been retconned as the Star Sapphire influencing her).
Also occasional foe Dr. Polaris.
The Spock: Depending on the Writer, the Guardians are either this played straight or deconstructed. Most recent characterizations show their coldly intellectual designs as badly flawed due to completely misunderstanding emotion.
Carol herself finds this irritating. She may wonder why some of the others in her corps wear comparatively conservative Silver Age versions of the outfit. For example, Miri Riam wears a distinctly "50's space girl" style costume, thus averting the somewhat naughty implications regarding Zamaron attitudes about the role of women in the universe. Unfortunately, and perhaps validated by their past histories, this may suggest something about the relationships that certain Star Sapphires such as Carol and Fatality have with the men in their lives.
Sufficiently Advanced Aliens: The Guardians. You have to admire a race that can make a starship capable of flitting across the galaxy in an afternoon, with integrated offenses and multispecies life support, in the form factor of a ring.
Survival Mantra: When Green Lanterns are hard pressed and in danger of succumbing to their fear, they can draw strength from remembering their oath and often, the worshipers of evil's might will once again learn the hard way to beware their power.
Take a Third Option: The Zamarons capture Carol Ferris and Jill Pearlman, two of Hal's girlfriends, and try to make him choose which of the ladies will be his mate... which will make the chosen girl be possessed by the Star Sapphire symbiote (again). What does Hal do? He plants a kiss on the Zamaron Queen, which makes Star bond with her instead.
Tome of Eldritch Lore: The Sinestro Corps has the Book of Parallax, which contains everything every Sinestro Corpsman has ever done or will do in the name of causing fear.
Later on we see the Book of the Black, penned in the tainted black tears of Scar, an undead Guardian.
There is also the Book of Oa which predated both of the above appearance-wise which tells the story of every Corps member, prophecies concerning the Corps, and the new Ten Laws. Of course, it's more of a Great Big Book of Everything as it isn't ominous... usually.
Too Dumb to Live: Sinestro has very sympathetic reasons for questioning the Guardians' authority.
Took a Level in Badass: Johns has pulled this with a number of characters. Sinestro went from being a good arch-enemy to Hal and already badass to becoming a full-blown Magnificent Bastard. Sodam Yat gaining the powers of Ion, even Black Hand gaining his own superpowers pre-Blackest Night was a nice level up in bad ass.
Very Special Episode: The "relevant" period in the '70s with Green Arrow. Showed up again during Judd Winick's run as writer in the Modern Age, though Winick's versions of said stories were widely panned for being way more Anvilicious than the O'Neill/Adams stories, which used science fiction allegory for their stuff.
The series originally had tendencies toward this anyway, though lapsed into Values Dissonance now. Carol was originally unambiguously Hal's boss, and was never shown to be less than competent at this. Tom Kalmaku was an Inuit, not only entrusted with Hal's secret identity, but also the source of his power and, in one story, fills in as a replacement Green Lantern. Both of these characterizations date back to the late 1950s.
Walking the Earth / The Drifter: Hal Jordan during the first half of "The Road Back" storyline. Guy Gardner can't take the fact that Hal is doing this and keeps antagonizing him. Hal eventually snaps out of it.
Weaksauce Weakness: The colour yellow. Fortunately it's not really as much of an issue since experienced GLs can easily overcome it.
"War Of The Green Lanterns" - Fallen Guardian Krona re-corrupts the central battery with Parallax, turning the entire Lantern Corps (Save Ganthet & the 4 human Lanterns) into his slaves, and infecting the Guardians with the other emotional entities; John kills Mogo to stop anymore brainwashed Lanterns being recruited, which leads to Sinestro losing his yellow ring and rejoining the Green Lantern Corps, whilst Hal kills Krona (Which shouldn't be possible due to the Guardians using failsafes to prevent the Lanterns from turning on them) to free the other Guardians, who dismiss him from the Corps to protect themselves in case he went rogue.
The 2012 Annual - The Guardians give Black Hand a power boost so that he can kill Hal & Sinestro, getting the two of them out of the way before they use their Third Army to destroy the various Lantern corps.
Women Are Wiser: The author's reason why the Star Sapphires are all female. Then again, the Sapphires use energies at the far end of the spectrum and are more likely to act crazy as a result.
The Worf Effect: In Green Lantern: Rebirth and Sinestro Corps War, the first thing Sinestro does upon showing up is beat the hell out of Kyle Rayner, even on the latter occasion when Kyle has a huge power boost. This is done just to make Sinestro look badass.
A bit of a subversion. In the first case, Sinestro ambushes Kyle — when Kyle regains his bearing, he badly scars Sinestro, wounds that he still bears years later. In the second, Kyle's disoriented, has had his powers curbed by a boobietrapped ring, is outnumbered 7200 to one, and even then still needs a Diabolus ex Machina for Sinestro to properly beat him.
Yandere: The Star Sapphire takes advantage of emotionally-troubled women and turns them into this.
You Have 48 Hours: One or more of the GLs face deadlines like this from the Guardians or some local authority often enough; in Final Crisis, for example, they are given 24 hours to save the universe.
In the 1981 miniseries, Tales of the Green Lantern Corps, the GLCs only had 24 hours to stop Krona and Nekron, after the Central Power Battery was destroyed.
In Blackest Night, Ganthet reveals that any Lantern's Power Ring can deputize someone for 24 hours.