Made a Slave: Even in humanity's darkest hours, there are still some people making profit from selling others to the capital's underworld. Specifically this would have been the fate of Mikasa and her mother (if she wasn't killed) if not for Eren rescuing her and putting them down like the dogs they were.
Made of Plasticine: Titans fall apart surprisingly easily. Don't think this makes them much less of a threat, though — their Healing Factor more than compensates. Particularly obvious when the Rogue Titan punches another of his kind, and ends up taking off its head and losing most of his forearm.
Male Gaze: Discussed in Episode 17, when Reiner refers to the FemaleTitan as having a "nice ass". Considering it's only partially covered in skin, he was probably making an inappropriate joke. (Alternately it may have been a personal in-joke, considering he's the Armoured Titan and knows the Female Titan is Annie, who probably has quite a "nice ass" in her human form.)
Martyrdom Culture: The military does not focus upon victory, but encourages soldiers to die as bravely and in as useful a fashion as possible. Many of the characters, similarly, seem obsessed with finding a way to die in as useful and meaningful way as possible. Eren goes out of his way to call bullshit on this as often as he can.
Sasha's introduction in Episode 3 when the Drill Sergeant Nasty spots her eating a potato in formation (breaking bearing is the least of her problems). While the drill instructor is distracted with chewing Sasha out, everyone shoots her horrified looks.
It occurs later in Episode 5, when Sasha reveals she "borrowed" some meat from the officers' rations.
The Scouting Legion gets one when they see that the walls hide Titans in them.
Mauve Shirt: Titans find recently introduced and named characters to be very tasty.
Meaningful Look: Just after her true identity is revealed and she is overpowered, the gagged Annie pointedly makes eye contact with Eren, who looks extremely distressed when he sees her seemingly helpless. This is even more obvious in the manga, and serves to highlight the respect they hold for each other. See the SnK wiki for the relevant panels.
Medieval Stasis: The only major innovation in the past century has been the development of the 3DMG. Everything else is firmly planted in the late end of the Dark Ages (or in the case of the Inner Walls, the Victorian/Edwardian periods). Justified. The Central Military Police have been seeking out and murdering any intellectual thinkers who pushed people to ask questions and seek answers, as well as people who tried to innovate. One unlucky couple was two steps away from inventing a working hot air balloon before the Central MP stepped in. They justify this by saying it ensures stability.
Missing Mom: Eren and Mikasa's mother, Carla. Her death was the Cynicism Catalyst behind Eren's violent hatred of Titans and his vow to destroy all of them.
The Mole: Annie, Bertolt, and Reiner are agents sent to infiltrate the military and destroy the Walls, who end up Becoming the Mask to various degrees. Ymir also secretly joined the human ranks, but independent of the others. She compares herself to her love interest, Krista, in that both rejected their pasts and tried to start new lives. How true this is, remains unclear.
Mood Dissonance: Episode 25 of the anime portraying Annie as sympathetic through flashbacks of her past, while simultanously portraying her Titan form as ugly and monster-like as possible thanks to Titan Eren's beating of her.
Mood Whiplash: Hope Spots show up frequently. One moment the situation can be hopeless, and the next moment we're treated to light-hearted character development. The reverse can happen just as often.
Even the funny moments are subject to this, such as a flashback to Mikasa and her parents where they pass the buck on The Talk, when there's a knock at the door...
An extreme example is Eren accidentally forming (part of) a Titan body in front of the Survey Corps for the first time. The tension builds up rapidly as the Survey Corps intensely yells demands at him and are a hair-width from closing in and killing him... only for Hange to arrive and go absolutely, hilariously, rabidlySQUEE over it, immediately defusing the situation.
Another example comes from the capture of the Female Titan. Eren and the rest of squad Levi are triumphant, and joking about who pissed their pants on their first mission. Then the Female Titan escapes and brutally murders squad Levi, except for Eren, who can only scream in despair, as he's too far away to do anything about it.
The anime tends to play this up for as much dramatic effect as possible, and to make the following tragedies just that much more tragic.
The first few episodes are a good indicator for this.. Episode 1 and 2 are absolutely brutal, as they cover the Titans' breach of Wall Maria, and the subsequent mass starvation. Episode 3 is basically an extended comedic introduction for the supporting cast — slapstick, punchlines, the whole deal. Then, by Episode 5, people are dying en masse again.
Of course, even the episodes that end on a dramatic and/or depressing note are followed by the calm ending song.
Morality Pet: Krista is this to Ymir, motivating her most heroic moments. Eren and Armin manage to befriend Annie, bringing out the kinder aspects of her personality. The members of the 104th, and Connie in particular, became this to Reiner and contribute to his eventual Sanity Slippage.
More Expendable Than You: Entire squads of soldiers are tasked with throwing their lives away if it means keeping Eren safe, because of how valuable his special abilities are.
More Dakka: Hundreds of hook-tipped wires are fired explosively from barrels in the attempt to capture the Female Titan, giving off this effect.
Morton's Fork: After Eren is exposed as a Titan Shifter, Weilman gives him a choice at cannonpoint: admit he's a traitor or say he's human. Eren, naturally, says he's human, and Weilman just fires the cannon anyway, pointing out that he can't prove it. Armin finds a way to prove it.
Mukokuseki: A noticeable aversion. Mikasa's Mixed Ancestry is commented upon, and she does indeed look different from the other characters with straight black hair and almond-shaped eyes. There is a wide variety of facialfeatures and eye shapes, many of which are stereotypically European in origin. The anime adds to this, making several characters Ambiguously Brown.
Mundane Luxury: After the loss of Wall Maria, land becomes scarce and food is heavily rationed. The majority of the population lives off grains, vegetables, and potatoes while meat and diary products are luxuries rarely available to those outside the wealthy Interior. Salt and Tea are also mentioned to be luxuries, and sweets are only shown being enjoyed by the nobility.
Mundane Utility: In Episode 15, the Survey Corps are seen using their 3D Maneuver Gear to... clean the grime off the walls and windows of an old castle.
Hanji and Levi have this reaction when they realized the Titans they experimented and killed were once humans.
Naked People Are Funny: It can sometimes be difficult to take the Titans seriously, with their giddy running, flailing arms, and how many of them look like giant naked people. This may actually be intentional, as it serves as massive Mood Whiplash when they flash their Slasher Smile and devour a beloved character.
The Needs of the Many: Gut-wrenching example. When Wall Maria is abandoned, there are too many refugees to feed and the food supplies look grim. The government's solution is to draft 250,000 people (20% of the population) to reclaim the lost territory from the Titans; only a handful survive. Pixis doesn't mince words about this and goes further to say that if Wall Rose falls, this time over 50% of the remaining humans are going to be sent to die.
This is the justification that commanders use in this series when they sacrifice their troops (except for the ones that are just plain Dirty Cowards).
Nerves of Steel: One of the Eye Catches mentions this among other things as a necessary to use 3D Maneuver Gear properly, since a soldier needs to be able to react and change directions in an instant to avoid disaster all while maintaining perfect balance. As far as characters go, you have to try pretty damn hard to shake Levi from his perpetual level-headed-ness.
Never Found the Body: Missing persons are grouped together with the dead in casualty reports since unlike other situations where desertion or being taken prisoner is a possibility, they are most likely dead without a body to leave behind. The exception to this is the 57th Survey Corps expedition where many of their dead did have intact bodies because the Female Titan stomped or crushed them instead of eating them.
Commander Erwin is savvy enough to not count the human inside the Female Titan dead even after her Titan body is devoured by other Titans since nobody witnessed said person's actual death.
Hitch and Marlowe believed Annie to have been killed during the Titan battle in Stohess due to this. Upon their return in the story, they learn from Levi how Annie was in fact one of the Titans fighting.
In Episode 22, while Mikasa and Levi attempt to rescue Eren from the Female Titan, who moments earlier had swallowed him, Levi formulates a plan to get him from the Titan. At first things go extremely well, with Levi managing to disable the Female Titan. Mikasa notices that the back of the Female Titan's neck is exposed, and tries to go for the kill despite Levi telling her to focus solely on rescuing Eren. Unfortunately the Female Titan is still able to move one of her arms, and attempts to grab Mikasa. Levi saves her, but he ends up spraining his ankle in the process of blocking the Titan's hand. While they do rescue Eren, the injury Levi suffered would end up costing him dearly later on after they arrive back inside the Walls.
Later on in the same episode, two soldiers berate Commander Erwin for not getting the body of their fallen friend. Levi tells them that it's too risky due to him having died near Titans, and that recovering the body at this point wouldn't matter, as he's dead anyway. Unfortunately those two guys went back anyway for the body, bringing two Titans with them. The friend's body falls off the horse, and one of them gets eaten. The second guy nearly suffers the same fate until Mikasa rescues him. To make matters even worse, the second Titan is chasing after the main party, and they're forced to dump the bodies of the other soldiers to lighten the load lest said Titan catches up and kills even more soldiers. In the end Levi hands the surviving soldier the Survey Corps patch from the first fallen friend, which is heavily implied to be a comforting lie and actually Petra's badge he took earlier.
When Reiner and Bertholdt reveal themselves as Titan Shifters, they admit that they heavily regret their actions and didn't fully understand the consequences when they began their attack, to the point where Reiner has experienced Sanity Slippage to escape the overwhelming guilt. It's implied that a little kindness here could have broken at least one of them into a complete Heel-Face Turn, or set them up to do so later on... but no, Eren promises to murder them as excruciatingly as possible.
In a Catch-22 situation, Reiner reveals that the Titan Shifters are willing to leave humanity alone if Eren comes with them willingly. He likely would have done so, had the Titan Shifters not ruined his life by getting his mother and countless friends eaten by Titans. But it's implied that Eren's Titan shifting abilities were given to him as a result of the attack on Zhiganshina; if that event had not occurred, then there would be no second option in the first place.
Eren points out that the greatest mistake of Annie, Reiner, and Bertolt was teaching him how to fight.
Had Annie not spared Armin's life as she slaughtered her way through the Survey Corps, he would never had exposed her identity as the Female-type Titan.
Nightmare Fetishist: Hange, who has an unhealthy interest in the inner workings of the Titans. When they manage to capture Titans alive, it's her that winds up performing the experiments on them. Hange actually names the Titans she captures, and genuinely seems to feel bad about experimenting them. Which, in a way, points to how insane she really is, since she's the only one who actually shows sympathy to the Titans.
No Conservation of Energy: Titans produce a large amount of body heat, yet they will only eat humans, who haven't been available to eat in large numbers for nearly 100 years. It's implied that because of their lack of digestive systems, they eat humans just because they're tasty. If the observations about them slowing down when they're deprived of light is any indication, their bodies act like solar panels to absorb and use energy.
No Conservation Of Mass: It's unexplained where the mass/energy comes from to generate a Titan body by the Shifters. For what it's worth the body mass does seem to release a high amount of heat as energy when the human leaves it and it begins to disintegrate.
No-Holds-Barred Beatdown: Eren in his first fights against the Female Titan. His rage and determination during their second one in particular scares the crap out of her, particularly when her own brutal attacks and dismembering some of his limbs only slows him down slightly. It gets to the point she tries to escape him by climbing up the Wall, only to be stopped by Mikasa.
No Ontological Inertia: A Titan's body quickly dissolves after their death. Their excessive amount of body heat makes dead Titan flesh spontaneously combust.
Titanic organic "armor" on the other hand does stick around even after being separated from the Titan. The Walls were apparently made this way.
Non-Action Guy: Armin himself said that it was "a miracle" that he passed the simulated combat section of the military graduation exam. He makes up for this by being a Guile Hero, coming up with vital strategies and uncovering the identity of the Female Titan, allowing them to lure Annie into a trap.
Nonindicative Name: The series could be more accurately named as Attack of the Titans rather than Attack on Titan which sounds like an assualt on the largest moon of Saturn.
A Germanic people battle giant Humanoid Abominations of varying size and deformity, as well as the revelation that some of them are seemingly human shapeshifters with the most significant ones less deformed and more intelligent than their Dumb Muscle kin.
Ymir's name in particular is drawn from a creation myth. This leads some unofficial sources to translate "Kyojin" as "Eoten".
Classical Mythology: Official sources translate "Kyojin" as "Titan", in a nod to the beings from Greek mythology. The Titan Cronus, in particular, was noted to have devoured his own children. The way Eren carried the large stone in the Battle of Trost also resembles the common depiction of Atlas carrying the sky/earth.
Not Enough to Bury: In the first chapter, a woman runs up to the returning Redshirt Army and begs them to tell her where her son is. The commanding officer gives her a small bundle which turns out to contain a severed hand — that's all that was left of him after the Titans got him. Apparently this is very, very common for the Survey Corps (if they can even find body parts).
Not Quite Flight: 3D Maneuvering is a process that combines gymnastics, Le Parkour, and Spiderman-esque Building Swing to achieve rapid aerial travel almost bordering on flight. During some long shots of soldiers maneuvering through urban environments, they're effectively gliding in between the buildings. The exceptions are when it's important to the plot for characters to have somewhat lengthy conversations mid-flight, in which case they will stop visibly using Building Swing and seemingly fly straight through their surroundings in order to talk cohesively.
Not So Different: In Episode 3, Eren is having a lot of trouble mastering the basics of the Maneuvering Gear. He asks various characters for help, but none seem to want to help him at first. Reiner and Bertolt, on the other hand, ask him why he's so determined to be a soldier, then tell him that they were also from a Doomed Hometown. They go with him to help him a bit with some extra training at night in an attempt to help him pass the training. This comparison becomes a bit more...interesting...when it's revealed that Reiner and Bertolt are also Not So Different from Eren in that they're both Titan Shifters.
Nothing Is Scarier: In Chapter 38, the soldiers trying to locate the breach at night express the fear that Titans could be anywhere nearby and they wouldn't know until it's too late due to the tiny pool of light provided by their torches.
The mere fact that after generations fighting the Titans, humanity knows close to zero about them, let alone how they even came to be.
No Zombie Cannibals: Titans don't eat each other, ever. Even Titans that have been seen attacking other Titans (like the Rogue Titan) aren't looking to eat them. However, regular Titans will attack and (try to) eat Human Titans, which is a problem for them.
Off Model: The second opening and ending are a bit off with the characters, during the ending when the prominent members of the 104th are lined together, it's noticeable that several heights are incorrect; for instance, Annie is taller than Eren when she's the second smallest, Krista looks normal sized, Armin and Connie are roughly the same height and are just about the same height as Eren.
The series as a whole has its moments of recycled (and often limited) animation and bizarre errors. Unusual for a Production I.G series, but justified in that Production I.G is not the primary animation company.note Instead, the main animation firm is Studio Wit, an offshoot of I.G These errors have been addressed in the Blu-Ray releases.
Some panels in the first 12 or so chapters of the manga... vary in artistic quality. Art Evolution definitely kicks in, but it can be a bit jarring for those who jump from the anime to the beginning of the manga.
Oh Crap: The standard reaction to a Titan's jaws closing in on soft human skull. Or just seeing one show up in general, which usually indicates things have really gone downhill.
The moment that Colossal Titan and Armored Titan showed up out of the blue and easily eradicated 100 years of protective solace reminded everyone of their place in the world as prey items.
Most of the Survey Corps soldiers unlucky enough to face the Female Titan only have seconds to realize that their opponent is no mere Aberrant Titan before she reduces them all to bloody stains.
On that same note, the Female Titan herself has this look after Erwin manages to successfully trap her inside the forest. She has that look again when fighting Eren in Titan form.
Reiner and Bertolt's reactions when Eren inadvertently commands a horde of Titans to kill them.
Older than They Look: Levi. He's shorter than Eren and looks to be a few years older than him but the author said he is surprisingly old compared to how he looks.
Only in It for the Money: Levi calls out the merchant guilds for being greedy pigs. Ostensibly they want Wall Rose permanently sealed off for humanity's safety but really they don't want Wall Maria to be retaken so as to profit from the lack of farmland and high number of starving refugees.
And now a properly animated omake exists, except 1. they don't follow the yonkoma plotline proper and 2. every episode ends with the Colossal Titan popping our heroes like pills for laughs.
Ominous Latin Chanting: The chanting in XL-TT, the series's go-to 'oh god we're screwed now' track, may not be in Latin, but it's certainly ominous.
One-Man Army: Mikasa can achieve on her own what three other special forces needed teamwork to achieve. Levi does the same but easier.
Only Six Faces: Avoided, especially after the Art Evolution and in particular among the main cast. Some of the varied facial features and body types are pretty impressive and the anime does an excellent job translating these.
Ontological Mystery: How and why did the Titans appear over a century back? How did they become so numerous as to make humans an endangered species when they don't even have a way to reproduce? Why is their biology so improbably weird? Were humans more or less technologically advanced before the coming of the Titans? Where exactly in the world is the Walled City? Is the setting another world where there are humans, or was it Earth All Along? What's the deal with some humans being able to turn into Titans? Who (or what) is Ymir?
OOC Is Serious Business: Levi who is normally reserved and solemn makes an effort to talk and joke with Eren after his personal squad was killed by the Female Titan. Eren points out he is rather talkative.
When Annie/the Female Titan was correctly outed, they began to smile and laugh madly, which was jarring because this was one of the very few times we see Annie having an expression other than cool indifference.
Chapter 51 gives us two. Erwin sports a creepy Slasher Smile after finding out the possibility that Titans were once humans. It was so unnerving that even Levi was alarmed/frightened by it.
Eren's shows an uncharacteristic amount of compassion and understanding to Annie when he finds out they are a traitor. This shows how deeply he respects her, and makes a very striking contrast to his more typical reaction when he learns that Reiner and Bertolt are traitors.
Out-Gambitted: The Central Military Police, who had tortured Pastor Nick to death and had been working for a shadowy conspiracy in order to kidnap Eren seemingly get the upper hand on Levi and co when they flush them out of their hideout and then enact a plan to kidnap Eren and Christa that goes off without a hitch. But then it turns out that Levi and the 104th were not only warned about their location being compromised, but also of the kidnapping plot: Eren and Christa were in a different area, completely safe. They'd kidnapped Armin and Jean disguised as Christa and Eren. Levi and co never even lost them.
Out-of-Genre Experience: The second OVA, which is based on the manga's "fake previews", takes the point of view of the supporting 104th trainees, and is meant to be much more comedic and nonsensical than the rest of the series.
The Outside World: Humanity has been reduced to a small population inside three different Walls (Maria, Rose and Sina), because of the Titans which are giant human-eating monsters who drove humans to their near extinction, anything regarding the world outside the Walls is considered heretic, the protagonist Eren, and his friend Armin are two kids who wish to see everything outside, given that humanity has remained inside for a little over 100 years, mundane concepts like the sea or deserts strikes them as fantastic.
Overtook the Manga: The anime only had 25 episodes, because the manga wasn't finished yet. It also caught way too fast with the source material, leaving out less than 15 chapters of content. Because of this, there will be a long delay for a second anime (if ever happens) to allow for story developments to catch up and to avoid this happening to such an extent.
Parental Abandonment: Eren has to watch his mother get eaten and his father goes missing shortly after. Mikasa technically suffers from this twice. Armin loses his grandfather (in the anime) as well, when he's sent out shortly after the fall of Wall Maria to try and reclaim it with a lot of others.
Parental Substitute: Hannes acts as a father-figure to Eren and Mikasa after their mother is killed and Grisha goes missing. Eren even calls him "Uncle" despite him just being a close family friend.
Jean's maneuver gear malfunctions while he's attempting to escape two Titans in Episode 12. He immediately notes the timing of it.
Eren is unable to transform in Episode 24 after finding out that Annie is the Female Titan, despite her shifting right in front of him. It takes Mikasa, Armin, and Jean (only Mikasa and Armin in the manga) to help him find his resolve and shift.
Plucky Comic Relief: For a shonen series, the tone is quite serious even when characters are hopeful and there's a distinct lack of deliberately humorous moments in between all the fighting, angst, character development, and solemnness... except for Sasha, the resident Big Eater. Later on Hange ZoŽ, Bunny-Ears Lawyer and Cloud Cuckoo Lander extraordinaire, helps out with the funny moments too.
Shoo Out the Clowns: Sasha becomes visibly shell-shocked during the Battle of Trost and soon not a funny thing comes out of her mouth. She even shows up less than the other Trainees of the 104th as the battle goes on. When she becomes more prominent later on, it is in a much more serious capacity. Similarly Hange never quite loses her quirkiness but she fills more serious (and Badass) roles as time goes on.
Posthumous Character: Marco dies very early on in the series, but it's this character's death which jumpstarts Jean's Character Development which leads him to inspire others to join the Survey Corps, and also helps Armin deduce the Female Titan's identity.
Power Incontinence: It turns out that Eren's Titan transformation the second time around was quite uncontrollable, even attacking Mikasa, his sister. As it turns out, he's in some kind of dream state, where things are as they were before the Titans breached the Wall. The last time, when he killed the Titans, was also apparently a dream-like state to him. In other words, his sub-conscious might exert some influence on his Titan form.
Power Of Hate: in order to transform Eren needs to be in pain (usually done via self harm) and have a specific goal in mind, which is handy seeing as his sheer hatred of titans gives him a very clear and precise goal when he transforms: to murder every last titan he sees.
Power of Trust: Horribly, horribly subverted. 'Trust' is synonymous with 'doomed, with extra grief and guilt on the side, hold the silver lining'. Eren learns this the hard way in Chapter 27.
The Power of Friendship: What ultimately causes the Titan Shifters' plan to fall apart. All three genuinely started to care about their fellow Trainees, and this causes them to begin making mistakes that expose their identities and compromise their ability to carry out their mission.
The Power of the Sun: Titans are solar powered. The researchers have to occasionally expose the captured specimens to daylight, so they don't die. They actually don't derive any nutritional value from humans, which leaves in-universe researchers just as puzzled as the readers. This makes the nighttime attack on Castle Utgard that much more of a shock.
Pragmatic Adaptation: The anime is currently this, the first episode adapted all of Chapter 1 and some of Chapter 2. Episode 2 adapted part of Chapter 2, and expanded on some elements. Episode 3 seems to adapt Chapter 15 and 16, making the story chronological, instead of having them as flashbacks after the the Battle of Trost, allowing us to get to know the characters whose lives are in danger.
Primal Fear: Mixes Giants and Being Eaten Alive together for a nightmare of a world.
And in Eren and Mikasa's case, "being a small child and watching your parents get killed."
Punched Across the Room: The Rogue Titan does this a couple of times, punching various Titans and sending them flying.
Pyrrhic Victory: Humanity finally wins one battle against the Titans in Episode 13 during the Battle of Trost. However, it came at a high cost, since hundreds died or were missing in action, and several hundred more were wounded, all to just retake one small town. As the narrator states the hefty casualty count and how none of the survivors wanted to celebrate the win due to how many people they lost.
In Episode 25, the Raid on Stohess District arc (and the series finale) is one of these. Annie/The Female Titan has finally been captured and the Survey Corps/Eren are to be spared by the tribunal for now but at horrible, horrible cost, including hundreds of combined military and civilian casualties and a partly-wrecked Stohess district. The part that gets everyone questioning Was It Really Worth It? is when Annie encases herself in a block of ice, meaning they can get no answers out of her.
The idea of soldiers bravely fighting Titans against the odds quickly runs headfirst in a wall: normal people are flat-out terrified of a 45-foot tall, man-eating giant and often freeze up or run away when they actually face them. The few that are genuinely brave enough to charge in without hesitation are regarded as... not quite right.
Just because mankind is facing extinction at the hands of an external foe doesn't mean that everyone will magically forget their interpersonal conflicts.
Recap Episode: Episode 13.5. This wraps up the Trost arc and makes sure everyone is up to speed before Episode 14, where we get a new intro with a bunch of You Should Know This Already. Namely: The focus is now on counterattack and retaking Wall Maria, the top 10 of the 104th survived Trost (minus Marco) and, with the exception of Annie, who chose Military Police Brigade, now serve in the Survey Corps, and of course Eren is a Titan Shifter fighting for humanity.
Re Cut: In the form of Director's Cut. Seen in the anime adaptation in which most changes were made on the author's request:
Episode 22 includes a lot of Tear Jerker not seen anywhere in the original Manga. In fact, there's over 11 minutes of Filler that the author thought was good enough to be in.
Episode 23 features Anniehisterically laughing when confronted by Mikasa as opposed to the calm, defying smile from the manga. The author said the change was made because the expression he gave her in the manga didn't actually fit the moment nor her emotions.
Reiner is the Team Dad, prone to acting without thinking things through while Bertolt is The Quiet One. A villainous example, with Reiner conflicted due to his attachment to their fellow Trainees while Bertolt appears to still be loyal to their mission.
Red Shirt Army: The Survey Corps, of which the main characters are an integral part. Their job is to literally "die as heroically as possible". This is driven home in the cruelest way possible during Commander Erwin's speech he gave to the trainees that thought about signing up in the Survey Corps, though on the other hand, the experienced soldiers of the Survey Corps are also the Badass Army (of the story), especially compared to the Garrison who man and reinforce the Walls.
The Garrison troops fall into this trope if the Titans breach a Wall, and are killed pretty easily. When the story starts literally all they can do is die to buy the refugees time to evacuate. Five years later, they are a little more competent and manage to hold the Titans off longer, though they still die like flies.
As it turns out, the Military Police Brigade members are this as well. Jean notes that their members keep getting devoured when we finally see them in action during the operation to rescue Eren from the Titan Shifters. On paper they are the most competent branch as only the top graduates of each Trainee Corps get to join, but they have no real experience fighting any Titans, and most members are implied to have been seriously neglecting their training because they didn't think they would ever have to fight.
Refuge in Audacity: Commander Erwin's plan to have Levi viciously beat the crap out of Eren in the middle of his trial in order to both defuse the situation and grab everyone's attention for his own proposal probably wouldn't have worked if it wasn't so over-the-top. Even the commander of the Military Police Brigadewho was trying to have Eren executed a few moments ago is stunned at how far Levi goes.
The Remnant: The Walled City is pretty much all that's left of human civilization (at least as far as it's known), the ruling government emerging from the world's united stand against the Titans.
Required Secondary Powers: Supplementary Materials note that using 3DMG requires very high amounts of coordination and balance (borderline-acrobatic levels) to use, much less pull off fancy maneuvers that Survey Corps veterans are seen using, as well as high leg strength, good aiming skills while mid-flight to actually land grappling hooks, and Nerves of Steel to keep it all together and not lose balance when disaster strikes (it's even stated that instructors will cut the cables on recruits to test their mettle). Also, one would presumably need to not be afraid of heights and be motion-sickness resistant.
Rescue Romance: Mikasa's undying devotion and implied romantic feelings for Eren seem to stem from how he saved her life when they met.
Revenge: Why Eren wants to kill every Titan really bad.
The Revolution Will Not Be Civilized: The Survey Corps. They try to avert this trope as long as they can, but then the government sends in the 3DM death squads (think about how awesome 3D-Maneuver gear has been used against Titans. Now think about what would happen if you traded the blades for guns installed in the grapple controls.) and sends in serial killer Kenny Ackerman, so they have to step up their game. Armin murders a hesitating Secret Servicewoman to save Jean, and it gets worse from there:
PLEASE ADD MORE INFORMATION AS THE SERIES CONTINUES.
Roaring Rampage of Revenge: Eren, frequently, when he assumes Titan form. In Episode 21, he includes actual roaring, after he watches the Special Operations Squad get literally crushed by the Female Titan.
Pretty much the whole series is Eren's quest for revenge on the titans for the last hundred years and all the trauma he's experienced.
Mikasa tends to do this whenever something happens to Eren.
Averted with Levi after his personal squad is killed by the Female Titan. He had every reason to lose it but instead, he kept a leveled head about the situation, noting it was more important to rescue Eren than go for revenge. He delivers an epic beatdown nevertheless.
Rousing Speech: Subverted in Episode 7. Sasha tries to get everyone to pull together saying "If we work together..." but clearly not believing it herself. Mikasa then shows up and sees that the remaining soldiers are too scared to fight, and she herself looks a little distraught having just found out that Eren got eaten. And instead of a big speech, she just insults them and tells them to die like cowards and heads off to fight more Titans. Played straight in that it works.
Rule of Cool: 3DMG in reality would encounter much the same problem jetpacks do, not enough fuel. And operating one safely, forget it. Damn if it doesn't look cool though.
Rule of Symbolism: When carrying the boulder to block the gate in Trost, Eren bears a striking resemblance to the Greek Titan Atlas.
Rule 34: Titans have no reproductive organs. This hasn't prevented fans from creating Titan-centric porn.