Season 3 introduces the city of Zaofu in the Earth Kingdom that was founded by Metalbenders. It consists entirely of clusters of palace-like buildings in the shape of flowers, all made out of stainless steel, and during nighttime the benders close their "petals" around them.
Despite the generally Early-Twentieth Century level of technology present in the show, the Equalists seem to have mastered high-energy, low-mass power generators or batteries, giving their mooks electrified Kali-sticks and Power Palms. This is especially surprising taking into account that the city uses lightningbenders for power generation.
As of season 4, the Avatar world holds the rare combination of a world with directed energy weapons but no conventional firearms.
Even worse, it has giant mecha suits, one of which is the size of a skyscraper, despite not having developed any kind of advanced circuitry, let alone computers, to control such monstrous machines. Justified as the whole thing is controlled by metal bending.
Scooby Stack: In "The Guide", we get a rare two-sided one, as Kya, Bumi, Pema, Jinora, Meelo and Ikki all peep in around the edges of a doorway on Tenzin admitting that he has never been able to make it to the spirit world.
Screw the Rules, I Have Money!: The Wolf-Bats pay off the referee in the pro-bending Championship so they can cheat without being called on it; by their third round with the Fire Ferrets, it is so blatant that the announcer calls them on it. It's implied by Amon that this is hardly unusual for them.
This is also true of Varrick, who is using his money to nefarious purpose, but is still a respected figure.
Senseless Sacrifice: In "Turning the Tides," Lin stays behind to hold off the Equalists and gets her bending removed. In "Endgame," we learn that the Equalists managed to capture Tenzin and his family anyway and are planning to remove their bending at a mass rally.
Series Continuity Error: In season 3, metalbenders (a Red Lotus mook and Suyin) are able to bend liquid metal when Metalbending is actually achieved by moving chunks of earth trapped inside solid metal, causing the metal to bend and warp into the desired shape, which would obviously be impossible for a liquid, even if we were to accept that solid bits of earth were somehow safely forced into and subsequently pulled out of Korra's bloodstream.
Sex Sells: After essentially inventing silent films (or reinventing them into talkies), what is the first thing Varrick decides to do with it? Get the hot chick to pose for the camera.
Shame If Something Happened: Varrick does this to Mako, stating it would be a shame if something happened to Asami or Bolin. When Mako refuses, he frames Mako for the robbery of Future Industries.
Asami, who subverts all the romantic rival and Woman Scorned plots and every single stereotype associated with her position. Notably, she's a wealthy, beautiful heiress who turns out to be great at fighting, a savvy businessman and engineer, a skilled race-car driver, and also unfalteringly kind and sweet. When her father's revealed to be an Equalist, she not only refuses to join, calls him out for letting his grief justify a vendetta, and almost a year later cheerfully refers to him as "diabolical". She also gracefully accepts her loss in the Korra-Mako-Asami Love Triangle.
Suyin Beifong. With her troubled past and her admitted harbouring of pirates, traitors, and conspirators within her city, you would expect her, as Lin does, to be hiding something, even to be linked to the Red Lotus. And you'd be absolutely wrong! Turns out her redemption story is as honest and true as can be.
Shell-Shocked Veteran: While she might not have fought in a war, Korra has this reaction after her battle with Zaheer. She has trouble fighting, and is constantly haunted by a vision of herself following her around the world.
Ship Sinking: Borra note Bolin and Korra was the first victim of this half way through season 1. Season 2 ended saw both Makorra note Mako and Korra and Masami note Mako and Asami get sunk. In a post series blog, Bryan stated that even if they didn't follow through with making Korra and Asami an item, they never had any intentions of having Korra and Mako get back together.
Shoo Out the Clowns: Averted with Naga. Bolin tries to protect Naga and Pabu by telling them to stay put away from the fight in the two chapter finale; turns out Naga and Pabu save Asami and him when they get captured and that Naga is quite the fighter.
Shoot the Hostage: In "Kuvira's Gambit", Kuvira uses her giant mecha to blow up the factory where Baatar Jr. is being held, having confirmed that Korra is there with him.
Tenzin has this relationship with his siblings Kya and Bumi. When they were children. Tenzin was very serious while his siblings were rather rambunctious. In the present we've seen that Tenzin is serious (usually), bald, and monk-like while Bumi is "a wild man" in the armed forces of the United Republic with a head full of anime hair; meanwhile Kya is unmarried and traveled all over the world to "find herself" (which Tenzin saw as abandoning her family) while Tenzin settled down and had a large family. Tenzin and Kya are benders with a spiritual/healing, while Bumi is a Bad Ass Normal military man/walking disaster area.
In their youth, Lin and Su were complete opposites. Lin became a cop to follow in her mother's footsteps, while Su actively hung out and worked with criminals to draw her mother's attention. This continued into adulthood, with Lin staying firmly rooted in Republic City while Su left to roam the world.
Sickeningly Sweethearts: Mako and Asami are too much for Korra to handle, although her own feelings for Mako probably contribute.
Sigil Spam: Once you see it as the Season 4 trailer emblem, you can see the Metal Clan symbol everywhere in the Zaofu scenes in Season 3.
Sliding Scale of Villain Effectiveness: High. The Equalists present a formidable threat to the Avatar and Republic City. Neither Korra nor the city's official police have been able to stop Amon or his agenda until their ultimate defeat in the season finale.
Same for the spirits of season 2: they can shrug of all but the most powerful bending and it takes special bending altogether to purify and/or turn them. Their leader is even tougher and they come very close to winning forever.
The Red Lotus of season 3 uphold up the trend by being exceptionally good at both combat and strategy; in fact, even though they're also defeated at the end of the season, one of their main victories remains completely unreserved; the plunging of the entire Earth Kingdom into anarchy. Their leader is also the only Big Bad to successfully kill someone onscreen.
Season 4: Kuvira begins the season by uniting the Earth Kingdom with Leonine Contracts then refuses to step down to the (admittedly rather incompetent) Earth Prince Wu, declares it an empire and herself the Emperor, takes over Zaofu by trapping Suyin and her two sons and has the rest of the family sent to a reeducation camp and nearly curb-stomps Korra, has been purging her empire of dissenters and non-native residents (though not killing them as far as we know), and her desire to make spirit vines into weapons of mass destruction is so horrible it makes Varrick grow a conscience and turn against her. Highly effective indeed.
Slobs Versus Snobs: The relationship between the more materially-focused Southern and the more spiritually-focused Northern Watertribes seems to be like this. Turns out there's something more to it.
Upon learning that Korra was the Avatar, the Order of the White Lotus set up a large compound in the Southern Water Tribe for her to live in, to fulfill the promise they made to Aang to protect his reincarnation. There, Korra underwent her Avatar training, under constant watch from the Order. She was allowed to leave, but only with supervision and as long as she did not go outside the South Pole. When Tenzin tried to delay her Airbending training, and thus ultimately her freedom from the compound, Korra ended up running away in order to follow him to Republic City.
This is eventually revealed to have been set up because of Zaheer's previous attempt to kidnap Korra when she was a child. They were imprisoned because they got caught in the act.
For Korra's airbending training, Tenzin attempted to set up something similar on Air Temple Island. This fell apart remarkably fast.
The first humans that lived in the lion-turtle cities knew nothing about the others and only ventured out into the world for food. This changes after the spirits leave for their own world and the humans are free to spread out.
Small Steps Hero: Korra decides to risk unleashing 10,000 years of darkness on the world just to save the life of one girl.
Snowlems: Ikki suggests that Katara use waterbending to make snowmen chase the children for fun.
The pro-bending ring is far enough above the water below that you'd expect injuries, at least from the non-Waterbenders, but this trope is in full effect.
Waterbenders in pro-bending are the only ones allowed to hit their opponents in the head due to this trope.
In a nod to the previous series, when Korra jumps into the ocean from a great height, she bends the water up to herself to soften her landing.
So Last Season: In Book 2, the Dark Spirits are immune to normal bending, even Korra's Avatar State-enhanced bending. Bending can disperse them, but they reform quickly. Only Unalaq's spiritual waterbending has proven consistently effective when performed properly, and it doesn't actually stop them, just calm them down and get them to leave. They're non-corporeal energy beings corrupted by darkness, instead of regular flesh and blood.
And then this trope gets applied to the spirit-calming technique when it proves to be worse than useless against the vine infestation in Republic City.
Downplayed with Lavabending. In Book 3, it gave Ghazan by far the most destructive power of the Red Lotus. For example, he completely levels the Northern Air Temple with it. In Book 4, when used by Bolin, it is still quite useful, but it is no longer a Storybreaker Power.
Somebody Else's Problem: Even though Book 4 confirms that Toph is alive, she generally does not get involved in the struggle against Kuvira. She justifies this by stating that due to her age, she simply cannot keep up with younger benders like Kuvira, and points out this is exactly why Katara didn't get involved in the Water Tribe civil war.
The Equalists of Book One are group of non-bending revolutionaries led by the terrifying Amon. While they're quite dangerous (even having the backing of a major technology corporation), their influence only really extends to Republic City.
Chief Unalaq of the Northern Water Tribe in Book Two isn't personally quite as scary or as powerful as Amon, but he commands far greater resources (including a horde of bending-immune spirits) and his plans threaten the entire world. Additionally, he's serving a far greater evil: Vaatu, the spirit of chaos and darkness.
The Red Lotus of Book Three are exceptionally powerful anarchist benders with unique abilities (though nothing quite as broken as Amon's psychic bloodbending) who seek to eliminate all world leaders, but they have only four main members. Nevertheless, Zuko considers them capable of taking on the entire world, and they prove him right by assassinating the Earth Queen and successfully plunging the entire Earth Kingdom into chaos. It's also later revealed that the Red Lotus has plenty of mooks hidden across the entire world, with Unalaq once being one of them.
Kuvira becomes possibly the most powerful foe in Book 4, not necessarily in terms of strength, although she did come out on top in a Curb-Stomp Battle with the Avatar due to Korra still being weakened but definitely in terms of strategic skill and resources, having the military might of an empire behind her at the beginning of the season with the addition of a Humongous Mecha superweapon by the end of it.
Sphere of Destruction: Kuvira firing the cannon from her giant mech in the spirit wilds created a reaction that completely obliterated everything within a pretty big radius and sent a shockwave through the rest of the city, leaving nothing but a perfect semispherical crater at the site of the new spirit portal.
Spotlight-Stealing Squad: Mako and Bolin tended to overshadow Korra in previous seasons. For this reason, the writers let them have several moments in book 3 where they go off on their own while letting Asami be Korra's partner to maintain focus on Korra.
Spinoff Sendoff: The first episode features an appearance by an elderly Katara as one of Korra's trainers. She encourages Korra in her plan to run off to Republic City, helping set the series in motion.
Toph's daughter Lin Beifong is the captain of the police metalbenders in Republic City. In Season 3 we meet her other daughter (to another father) Suyin, who is just as stubborn and strong-willed as Toph and Lin. We also get to see Suyin's kids: Baatar Jr, Opal, Huan, Wei and Wing.
Aang and Katara's son Tenzin, who is teaching Korra to airbend just as Roku's descendant Zuko taught Aang to firebend. Tenzin also has two other siblings, Kya and Bumi, named for characters in the first series. Tenzin himself brings his wife Pema, and four children, Jinora, Ikki, Meelo, and his new born son Rohan .
Lau Gan-Lan, son of the ill-fated Cabbage Merchant, has set up a successful automotive company to rival Future Industries. Unfortunately, he seems to have the same bad luck as his father.
Zuko's grandson, General Iroh of the United Republic military forces, appears in the final arc to assist in the fight against Amon. Iroh, unlike other examples, actually has the exact same voice as his Grandfather.
We also briefly see Zuko's daughter, Izumi, who took up the title of Fire Lord when Zuko left the Fire Nation to act as an ambassador.
Earth King Kuei's daughter, Hou-Ting, appears in Book 3. Sadly, while her father was The Good King, she is a complete Jerkass evil tyrant and one of the villains.
Kuei's great-grandson, Wu, becomes a major character in Book 4.
Staged Populist Uprising: Amon, who claims he was gifted by the spirits to cleanse the world of all benders, is himself a Waterbender.
Standing Between The Enemies: Avatar Wan tried doing this between his old human friends who left the lion-turtle city and now were living in the wilds but not in harmony with nature, and his spirit friends who were furious at the humans for burning parts of the forest. Unfortunately, their minds were clouded by hate and when Vaatu arrived and empowered the spirits hatred, not even Wan bonding with Raava for a short time could quell their anger. He passed out and woke up, learning all humans were killed in the battle.
At first glance, Wan Shi Tong's "little men in boxes" line sounds like a silly thing you'd hear in The Roaring Twenties or so. But remember who gave him that information: A bunch of foxes.
Zaheer spends most of the third season quoting a airbending master about achieving weightlessness and flight. In the finale, he is defeated when Korra wraps a chain around his leg and slams him into the ground, or in other words is quite literally dragged down to earth.
The spirit energy cannon's first appearance is mounted on a railway wagon. Being a directed energy weapon, that would make it a railgun!
Stereotype Reaction Gag: In "A Leaf in the Wind" Korra Downplays and Invokes this when she asks Bolin to teach her some pro-bending moves. He agrees but isn't sure how his earthbending will translate to her waterbending. She responds that she can earthbend, and Bolin freezes up before Digging Himself Deeper, stumbling through an apology about making assumptions based on her Water Tribe clothes. After letting him squirm a little, she allows that he was right, she is a waterbender, and a firebender, too. Bolin's brother, who saw her as just a common fangirl up to that point, does the math:
Mako: You're the Avatar, and I'm an idiot.
Storybreaker Power: Ghazan's lavabending is this. He can turn any rock into lava, which can only be blocked by an earthbender, whose rocks Ghazan can turn into more lava. It's rather telling that he is ultimately defeated when Bolin unlocks lavabending too, and Bolin still needs Mako's help to actually gain the upper hand on Ghazan. Even then, Ghazan ultimately kills himself instead of losing the fight.
Stylistic Suck: The Nuktuk, Hero of the South film presented in Night of a Thousand Stars is this trope... for the first half, at least.
Sudden Name Change: The "penguins" seen way back in the first episode of ATLA had their name changed to "penguin-otters".
Tonraq and the rebels' attempted assault on the harbor city became this when the Dark Spirits were found to be fighting alongside the Northern Water Tribe.
When President Raiko finds out that Unalaq will release Vaatu and their army of Dark Spirits will destroy the world, he refuses to mobilize his troops, because assaulting the South Pole would be suicide under these conditions.
Super Empowering: Lion turtles used to do this with humans via energybending, granting them the various bending powers.
Supernatural Martial Arts: Just as technology has advanced, so have the bending arts, with many hybridized styles shown even in just the first chapter in addition to the more classic bending styles. Mako and Bolin's styles show shades of modern boxing and kickboxing, despite wielding separate elements.
Suspiciously Similar Substitute: Unalaq to Tarrlok. Both are charismatic politicians who are also powerful waterbenders whom Korra allies herself with early on. They both also have a Secret Art that we've never seen in action before. They also both then seem to turn out to be a Well-Intentioned Extremist who is trying to use the Avatar to his own means.
Aang's children are a male Airbender who feels the weight of the world on him, a female Waterbender who tries to play peacemaker, and a male nonbender who has a lot to prove compared to the others. Where have we seen that dynamic before?
And then Tenzin's own children are also a stubborn boy, a mostly-sweet girl, and the one caught in the middle, so the pattern's shaping up to extend to a third generation, more or less.
After being captured again, Zaheer is placed in a high security prison that has him chained to the floor to counter his new-found abilities.
Take Our Word for It: No one ever explains just what Vaatu's "ten thousand years of darkness" actually entails. All that can be known is that humans will be annihilated, and Vaatu will reshape the world in his name.
Tall Poppy Syndrome: Benders believe that they are tall poppies that envious Equalists want to cut down.
Teens Are Short: Averted. Korra is as tall as most other adult women, Mako is very tall indeed, Bolin is still within a reasonable adult height even though he's shorter than his brother, and Asami is slightly taller than Bolin. It's part of the Art Evolution from the original series, which played this trope straight.
Jinora and Korra's varying execution of airbender footwork highlights their temperaments. The more showy Korra navigates airbending training gates with lots of energetic spinning. In comparison, Jinora's approach to the course is fairly clinical: she turns on a dime but keeps her upper body rigid.
The same goes for spirit healing: Unalaq's technique has a lot more rapid, circular motions to the point where it looks flamboyant, whereas Korra's is more controlled and firm, perhaps inspired by her airbending training.
In-universe, Tarrlok identifies Amon as his brother Noatak, despite Amon's appearance being concealed, by the distinctive feel of his bloodbending.
In "And the Winner Is...", the Wolfbats, having just cheated their way to victory, ask if anyone else wants to take them on. Amon answers the call.
In "When Extremes Meet", Korra taunts Tarrlok about having no water to bend after destroying his office (which had a wall fountain). Unfortunately, she forgot about another source of water nearby.
In "Harmonic Convergence," Asami, Bolin and Mako are flying an air attack against the South Pole, and Mako says, "There's no way they'll be expecting us!" Flipping off karma like that is a bad idea.
The Missus and the Ex: Mako has this reaction when with Korra and Asami at the same time due to his on/off relationship with both of them. There is a hilariously awkward moment in the first episode of the third season where he addresses both of them formally as if speaking to a superior officer because he just does not know how to relate to the two of them together. Does not help that the two women are good friends.
Tenzin as well, when Lin Beifong and his wife Pema are shown together.
There Are No Therapists: Averted. Lin Beifong goes to receive an acupuncture therapy to help her deal with the stress of encountering her sister again. While our world would call it an alternative therapy, it's the height of psychiatric medicine in Avatar-world. It works, after a fashion.
There Was a Door: Korra's Establishing Character Moment has her Earthbend the wall of her room to make an entrance. Her parents probably did not have that in mind when they wanted her to come meet the White Lotus members sent to verify her Avatar status.
Thou Shalt Not Kill: A notable aversion. Even heroic characters (especially Korra) sometimes threaten or aim to kill when they're extremely angry. Mako and Suyin have even done it, albeit in the heat of battle. Still, when Korra threatens a bound and helpless Bataar Jr. to get him talking, he immediately calls her bluff.
Throw the Dog a Bone: Cabbage Merchant, The Chew Toy and Recurring Extra of the original series, earned enough of a fortune during the peace times that he was able to found a technology company in Republic City. However, it's implied he or at least his successors are dirt cheap, because a lot of the company's product line is cheap knock-offs of Future Industries products.
Throw It In: In-Universe: Bolin (as Nuktuk) plants a kiss on Ginger, saying "it felt so right". Ginger is horrified, but Varrick likes it so much that he keeps the kiss in the film.
Book Three starts two weeks after the end of the previous season, and the denouement skips ahead a couple weeks, allowing the characters to recover (to an extent) from the injuries they sustained during the final battle.
Book Four is set three years ahead, with some flashbacks to fill in the gap.
Title Drop: The first three chapter names are mentioned by a character.
"Welcome to Republic City" is Gommu's cheery dialogue on realizing Korra is a Na´ve Newcomer.
Tenzin tells Korra the key of the airbending device is to be like "A Leaf in the Wind".
People are lured to Amon's rally to learn about "The Revelation".
To Hell and Back: In a way. Tenzin enters the spirit world to find his daughter, and enters the Fog of Lost Souls, which inflicts insanity on anyone caught in it, overcomes its effects and takes is daughter and his siblings out.
Token Romance: Appears to play this straight in Book 1. The Love Triangle subplot ends with Korra and Mako getting together, but not only does it contribute little to the main plot, it comes across as shallow, with the characters involved not getting a whole lot of friendly interactions together and only seeming interested in one another due to their looks. Book 2, however, deconstructs it. It turns out that Korra and Mako don't have any real chemistry together, they frequently break into arguments over the smallest of disagreements, and can never reconcile their differences. It culminates in them eventually breaking up. They do not get back together.
In "The Voice in the Night" while at Tarrlok's gala, Tenzin has to chase after his son Meelo, who has apparently decided that something offscreen is a toilet.
In "When Extremes Meet," Team Avatar joins hands and vows to stand by one another through whatever comes...and Meelo floats down onto their joined hands by using a fart to air bend.
In "Turning The Tides", Meelo is given to Lin to look after, who promptly tells her he needs to poo... and starts grunting. Lin understandably holds him with her metal cables at arm's length. Meelo also likes to airbend his farts as part of his combat style against the Equalists.
Meelo is very good at this trope.
Varrick dropping money out of a stuffed Platypus Bear's anus twice in "Civil Wars Part 2". Bonus points for one random guy shouting "That platypus bear is pooping money!" and the farting sound effects to top off the joke.
Tonight Someone Kisses: In perfect Avatar tradition, it was used as a teaser for "Spirit of Competition." The clincher? This happened the day before April Fool's.
The menu screen on the DVDs has clips that give away key plot points.
The trailer for Book 4 spoils Korra's meeting with Toph
Traumatic Superpower Awakening: Zaheer unlocks an advanced airbending technique when P'Li is killed, which severs his last earthly tether, enabling flight.
The Triads and the Tongs: The Triple Threat Triad, a pan-elemental bender organization that collects protection money from shopkeepers, and its referenced competitors, the Red Monsoons and the Agni Kais.
The waterbender from the Triple Threat Triad after Korra taunts him.
Korra when Tenzin cuts off the radio seconds before the pro-bending match being played is finished.
Tenzin displays this on hearing that Korra is participating in a pro-bending match.
Tahno gets one after Korra beats him in the tiebreaker.
Two-Part Trilogy: Books 2, 3 and 4 form one. While Book 1 is more of a self-contained miniseries that doesn't effect Book 2 in any significant way, Book 2, while having a standalone plot, has a stronger effect on Book 3, which is inter-linked with Book 4 in dealing with the conflict with the Red Lotus Society as the world undergoes great changes.
Undercover as Lovers: In "The Revelation" Korra grabs Mako's arm and leans in to provide a more convincing cover when they approach the bouncer at an Equalist rally.
Underdogs Never Lose: The Fire Ferrets were considered the underdogs going into the tournament. Subverted as the Wolf Bats win through illegal moves. Then gets double-subverted as the Wolf Bats did not get away with their victory, and they paid the price
In the Book 2 finale, Desna describes his father as a "deplorable man." He usurped the throne of the Northern Water Tribe by getting his brother exiled, invaded the South, created dark spirits, intentionally fused with an Eldritch Abomination, and tried to destroy the world, starting with Republic City. "Deplorable" might not be a strong enough word.
In "Day of the Collosus," when Bataar Jr. asks how Kuvira could betray him, Su only says that Kuvira is a "complicated person." Based on the slight pause, it seems she was about use some stronger language.
Unexpected Character: Iroh and Zhao's appearances in the Spirit World were unexpected to say the least, with no previous mention of them beforehand.
Unflinching Faith In The Brakes: In the Book 1 finale, Bolin is being attacked by mecha-tanks, which Naga unexpectedly stops by grabbing their grappling hooks and tugging. The mechas tumble over and stop just shy of Bolin, who never moves. Then he says "Whoa!"
Unflinching Walk: While pursuing Amon onto an Equalist zeppelin, Korra uses firebending to cause a large explosion. His mooks are knocked aside, but Amon casually boards.
Firebending's advanced technique of lightningbending, once only demonstrated by Azula, Iroh, and Ozai, is, after seventy years and an industrial revolution, mundane enough that firebender menial laborers use it to run the power plants. It is also noted that firebenders who are strong enough to use this gift are not common, though.
Metalbending, once Toph's unique innovation, has become a standard ability in Republic City's police force, Zaofu's city guard, and the Earth Empire's Elite Mooks. In this case, Toph herself was the founder of both the first metalbending school and Republic City's police force, her younger daughter was the one who founded Zaofu, and the Earth Empire was founded by a former Zaofu guardswoman. Additionally, the skill is still noted as being relatively difficult to learn.
Combustion Man's explosion-based combustion bending is still quite rare, allowing P'Li to remain a serious threat in Book 3, but the particulars of how it is performed are well-known, as are its weaknesses.
Asami is able to pilot a Mini-Mecha because its controls are similar to a Future Industries forklift.
General Iroh can pilot a airplane, to an extent, despite only becoming aware that they exist the day before.
The Unfavorite: Kya and Bumi according to their recollection that their father, Aang took Tenzin on vacation with him, leaving them behind.
Ungrateful Bastard: President Raiko expels Korra from Republic City after she had enough of being scapegoated by him and told him the spirits and the vines would stay until she figured out how to remove them without making the spirits angry. Also the Republic City Press who berate her despite her best efforts. Note, Korra's saved all their asses from Amon and Vaatu, yet no one in the city except for her friends step up to her defense.
Unskilled, but Strong: The first benders had no actual skill; they were given an element by their lion-turtle when they left the city, and gave it back when they returned. They never had a chance to train. Wan was the first to learn how to truly use his element, becoming the first real firebender after training with a dragon.
Hunter: The way Wan uses fire...I've never seen anything like it. It was like it was an extension of his own body.
In "The Revelation," Korra and Mako do battle with Equalist chi-blockers who are riding motorcyles.
In "When Extremes Meet," Team Avatar uses Asami's satomobile to attack, and defeat, Equalist forces staging a jail break. At one point it becomes a car vs. motorcyle battle.
Victory By Endurance: The Fire Ferrets win two matches by simply dodging or blocking their opponents' attacks until they've tired themselves out, at which point the Ferrets win with ease. Mako impressively manages this when it's three-on-one.
Villain Has a Point: All four Big Bads each had a point, which is actually discussed in Book 4. Their problem was that they were imbalanced in their belief.
Amon was all about promoting equality, but did so in a violent manner.
Unalaq felt it was wrong to lock away the spirits, but was ready to wipe out humanity for it.
Zaheer encouraged freedom, but did so suddenly, which made people go crazy.
Kuvira is essentially correct in her beliefs. The Earth Kingdom's monarchy was archaic, and the heir apparent was completely unprepared to provide the nation with the leadership and organization its people needed to rebuild from the chaos started in Book 3. She just overdid it, as the others did.
Villain Ball: Unalaq's plans might have succeeded if only he hadn't been so heavy-handed and petty in his execution. He takes the time to ruin his brother's life, even though this gains him nothing and alienates Korra, who he still needs to complete his plan. He also completely takes over the south, which also didn't win him any points with Korra. He could have gotten Korra to open both portals and she would be none the wiser to his plan, right up until it was too late, if only he had shown a little restraint. Even if he absolutely had to secure the portal to make sure no one found Vaatu, he could have just secured the portal and nothing else, which probably would have worked if he made up a half-decent excuse.
Hell, all the villains play basketball with this trope. Amon threw away what little point he had in favor of blowing up sports stadiums and attacking innocent people, Zaheer attacked the Northern Air Temple and held the airbenders hostage, and Kuvira tried to kill Korra after she had already won a fair one-on-one fight, with Korra having agreed to leave if she lost.
Villainous Rescue: When Tarrlok is about to flee the city with Korra as his hostage, Amon shows up and de-bends him, but he came to kidnap Korra too.
Villain World: This was what Vaatu and Unalaq wanted to create: A world where spirits rule over humans. They almost succeed.
The main setting of Book 3 is this. The Earth Kingdom is ruled by a tyrannical Queen, who extorts her own citizens, has the Dai Li proscribe her own people, especially Airbending children, and sends poachers to hunt down endangered animals, including Sky Bison, which are considered sacred animals to the near-extinct Air Nomads. The Earth Queen is dead, but now the Earth Kingdom has fallen to anarchy and chaos, which is exactly what the Red Lotus wanted.
Unlike Meelo, his lemur Poki vomits the berries onto the ground, then proceeds to lick them back up.
Walking the Earth: Korra at the start of Book 4 and its later revealed that Toph is currently doing this.
Wardrobe Flaw Of Characterization: Mako wears an old scarf at all times, even when dressing to the nines for a fancy date, because it's one of the few mementos he has of his parents. Something of an Informed Flaw; although some characters react to it as though it clashes horribly with his fine clothes, to the audience it looks perfectly normal, even stylish.
Welcome to the Big City: The plot of the first chapter, as sheltered Country Mouse Korra realizes Republic City isn't the shining beacon of harmony and prosperity she thought it was.
Well-Intentioned Extremist: All four Big Bads each championed a cause that was a legitimate concern, but in each case they went overboard in trying to correct for it, ultimately ending up going to the opposite extreme.
Lampshaded in Book 4 by Toph when she points out that Amon, Unalaq, and Zaheer were fighting for ultimately noble purposes (equality, bringing back the spirits, and freedom respectively), and that Korra could learn a thing or two from them.
Combined with Wham Shot, from "A New Spiritual Age". Not so much the line, but who is saying it.
Iroh: You two look lost. Maybe I can help.
And then we have this gem from "Darkness Falls".
Zhao: I am Zhao the Conqueror. I am the Moonslayer! I will capture the Avatar!
"The Metal Clan".
Korra: "Why didn't you tell me you had a sister?"
Lin: (tersely) "Half-sister."
From the season fourth's trailer: "THREE YEARS LATER". Also:
Korra: "I can't believe it...Toph?"
From "Korra Alone", when faced with a vision of herself in the Avatar State for the second time:
(the dog starts growling, facing the apparition)
Korra: "Wait... you can see it too?"
Wham Shot: Easily missed if you weren't paying attention or didn't know some of the mythology of the show from the first series. The first time Tarrlok bloodbends Korra and kidnaps her, the "camera" pans up to the night sky showing that there was a crescent moon, but not a full moon. Based on prior mythology, this is Beyond the Impossible.
The first episode of Book 3 starts with Bumi airbending for the first time.
In "Original Airbenders", Kai and Jinora are suddenly captured by what seems to be a normal group of thugs. However, their leader is wearing an Air-bison fur cape.
What the Hell, Townspeople?: Despite Korra saving the city from Amon, the city and the entire world from Unalaq, Korra depressingly notes she has an 8% approval rating in Republic City. Then President Raiko kicks her out after she stopped a new Airbender from committing suicide without anyone stepping up to call him out on his bullshit.
When the Planets Align: Happens every ten thousand years, signifying a harmonic convergence event. The energies of the two spirit portals combine and allow either Raava (Order) or Vaatu (Chaos) to dominate the other. The loser is absorbed and slowly gains strength until the next convergence, and the cycle repeats.
With Great Power Comes Great Insanity: This was the reason why bloodbending was declared illegal and why Hama was evil in the first place—the continued use of bloodbending causes waterbenders to go insane and develop an insatiable hunger for power—which was the case with Yakone, Amon, and Tarrlok frequent use of bloodbending turned them into even bigger monsters than they started out.
World-Healing Wave: In Book 3, it's revealed that the Harmonic Convergence also restored the presence of airbending in the world, granting it to many people who before could not bend.
The World Is Always Doomed: It seems like the end of the Hundred Year War just doesn't cut it. Every season, the world is always under threat; Book 1 featured the Equalists who, while mostly confined in Republic City seek to expand their campaign to eliminate all bending across the world. Book 2's Big Bad Vaatu seeks to plunge the entire world in eternal darkness. Book 3's plot features Korra having to stop a cabal known as the Red Lotus, who seek to eliminate all the world's governments and bring it to complete anarchy. And by the consequences of the Red Lotus, new doom has arisen in Book 4.
Korra even starts questioning why the Avatar should even exist if the world was going to be out of balance no matter what she does. She then gets reminded that that is exactly why the Avatar has to exist: to put down the imbalances before they ruin the world completely.
Wretched Hive: Tenzin acknowledges that Republic City has gotten a lot worse since his father's death, to the point that he considers his responsibilities as a councilman more important than teaching Korra.
Amon claims that his ability to remove a person's bending is a gift bestowed upon him by the spirits, who have determined that the Avatar failed in its duties of bringing balance to the world. Amon is actually simply utilizing another form of Wrong Context Magic; by combining bloodbending with chi-blocking he is able to strip away a person's bending ability.
Sokka discusses this trope in a flashback. While bloodbending without a full moon appears to break the laws of bending, Sokka quite reasonably points out that the fact that nobody has ever done it before does not mean it is impossible, given other examples of Wrong Context Magic that he encountered in the original series and especially when all evidence indicates that it actually happened.
The Red Lotus in Book 3 all have abilities that don't fit into the normal rules of bending.
Wuxia: As with its predecessor, a heavy genre influence.
Xanatos Gambit: Amon makes a public demand over the radio that the city government shut down the Pro-bending Arena and cancel the championship match. If it works, he shows that he can make the government fold under pressure. If it doesn't, his original plan goes forward and he demonstrates his power regardless.
Varrick can come off as playing Xanatos Speed Chess all the time in his plans to get support for the South, take over Future Industries and make boat loads of money. Hell his introduction can be seen as this: either no one tells him he's not flying (and he knows that they're all yes-men in his pocket) or someone points out that he's not (and he gets his claws on someone who isn't afraid to be honest). If Asami didn't follow his advice to send tanks to the south (which he stole) it wouldn't have mattered because in a matter of weeks he'd be able to buy the company out right because it was in trouble, he just didn't want to risk competition for the bidding...
Yandere: Eska could give Yuno a fair match in that department.
You Are Not Alone: In chapter eight, when Korra is crying about not being able to take the burden of saving the city alone, Mako, Bolin, and Asami come along and remind her she is not alone and they are there to help her save the city.
You Are What You Hate: Amon is not only a waterbender, but a bloodbender, which makes all his talk about how benders only use their powers to gain an unnatural advantage over others deliciously ironic.
You Keep Using That Word: Technically the words "electrocute" and "electrocution" exclusively mean "to kill with electricity", though they long ago passed the point in common usage where it can mean non-fatal shock (shock, or electrify, being the "correct" terms in non-fatal electrical incidents).
You're Just Jealous: After Mako wrongly accuses Korra of using his brother for some Operation Jealousy ploy, she sees through his facade and remarks that he is jealous. This seems to be a favorite tactic of Mako since he uses the same argument against Korra when she insists that Hiroshi is an Equalist and Mako believes she is only doing this because she's jealous of Mako's and Asami's relationship.