Armin Arlert

"I wonder if...just maybe...there was another, different path."

- Armin regrets the massacre at Liberio

Armin Arlert (アルミン・アルレルト) is an elite soldier in the Survey Corps. He is also a childhood friend of Eren Yeager and Mikasa Ackerman, and one of the two deuteragonists of the series. Although he appears to be among the physically weakest of the 104th Training Corps, his intelligence and strategic genius make him an invaluable asset, especially when paired with Hange Zoë. After the battle of Shiganshina District, he took the power of the Titans from Bertolt Hoover and became the Colossus Titan. He is currently an officer (上官) in the Survey Corps.

Human form
Armin has a boyish face, with large hazel eyes and a small pointed nose which is always distinctly a bit red. His blond hair is styled in a long undercut with bangs over his entire forehead. Armin has noticeably defined eyebrows and sideburns, indicating his age. His frame is, as it has always been, relatively small and lacking in muscle but not the definition. During the attack on Liberio, Armin is seen wearing a standard cloak for hiding purposes before he transformed. He is noticeably a bit taller and has his hair cut shorter.

As a soldier in the Survey Corps, Armin is seen wearing their revamped black uniform for the night raid on Marley.

As a teen Armin was rather short for his age, though he had a somewhat defined build. He had a round face with blond hair that is cut in the style of a bob and large expressive eyes with brown eyebrows.

In his childhood, Armin wore a long-sleeved single-buttoned jacket with a collared shirt, long dress-pants, and dress shoes. As a member of the 104th Training Corps, Armin wore the standard 104th Training Corps uniform with a white button up underneath.

Before the redesign of their uniform, Armin wore the standard Survey Corps soldier outfit. Underneath his short brown jacket, he had a white collared button-up shirt, similar to the one he wore as an adolescent. Like his comrades, Armin has supplemented his attire with a large green cape when participating in the expeditions outside the Walls and missions. He also wore long brown boots that reach up almost to his knees, as the other soldiers did.

Colossus Titan form
In his Colossus Titan form, Armin is entirely skinless and is extremely tall, similar to Bertolt's Titan. His Titan has elongated, skinny arms reaching past its knees and very muscular legs with short thick feet. His Titan's feet are shaped so that it can stand without falling over due to its proportions and height. Armin's Titan's upper body is also fairly skinny, with an exposed rib cage on the front and sides. Its face is missing almost all of its skin, which is replaced by bare bone. The eyes of Armin's Titan form are sunken in and somber, with muscle surrounding them. Armin's skeletal nose is undeveloped on his face, and his teeth are shown due to the lack of skin on his cheeks. However, unlike the previous Colossus Titan, Armin's Titan has lips which are surrounded by some muscle. What makes Armin's Titan particularly unique is the exposed windpipe that can be seen at its neck, with only two tendons in front of it. It also lacks visible outer ears.

Pure Titan form
Before inheriting the power of the Colossus Titan from Bertolt Hoover, Armin's Pure Titan form shared a number of traits with his human form. It had blond shoulder-length hair, a relatively small body with a lipless mouth and black eyes as well as a skeletal nose. While its exact height was unknown, it was shown to be big enough to peer over a three-story house rooftop.

Personality
Even when he was young, the naturally curious Armin had a deep fascination with the world beyond the Walls. As a child, he found and studied an illegal book about the outside world that was owned by his grandfather. He told Eren Yeager, his best friend, about the book and the information that was it contained. Armin was branded a heretic by other children for his unusual interest in the outside world, and was thus frequently picked on. Too timid to defend himself, Armin would often rely on his friends Eren and Mikasa Ackerman to protect him from local bullies. This, coupled with his frail physique, was a source of much shame for Armin, leading him to have poor self-esteem and to believe that he was a burden to others. Because of this, Armin has always been very eager to prove his worth. As a child, he hoped that one day he would be able to consider himself a true equal to his friends.

When Armin got older he enrolled in military training and after graduating he joined the Survey Corps with Eren and Mikasa. He wanted, first, to try to make a good and meaningful impact on the world, and second, to realize his dream to see the outside world. His curiosity has remained a strong personality trait from when he was young, driving him to do whatever it takes to ensure humanity's triumph over the Titans.

Armin continued to have low self-esteem during his training years and for a short while after graduation. During this time Armin considered himself to be useless due to his lack of physical strength and skill. However, soon after graduation, he came to learn that his mind is an equally valuable asset to the military, and that he can use his brain to help people. Consequently, Armin gradually gains confidence in himself and his abilities. Nonetheless, he can still be hard on himself at times. The fact that he is so willing to sacrifice himself to achieve a goal shows that he still does not value his own life as much as he should.

Armin is exceptionally loyal and selfless. He constantly worries for the safety of his friends. He is always prepared to throw himself into dangerous situations to save them, even offering to sacrifice himself for Mikasa. When he, Jean Kirstein, and Reiner Braun had to decide who would be left behind without a horse, Armin immediately offered himself without hesitation. When Jean was injured in battle, Armin rushed to his aid, placing himself in danger as well. Although he and Eren were determined to live their dream of seeing the outside world, Armin was content to give his life in order to defeat the Colossus Titan and to have his dream fulfilled through Eren. Armin is also very level-headed, keeping Eren and Mikasa under control whenever their emotions get the better of them. He has talked down a fight Eren started with a soldier, and restrained Mikasa from acting rashly during Eren's military trial.

Armin is a very analytical person. He likes to think deeply about situations and solve problems using his mind. These personality traits, in conjunction with his intelligence, good judgment, level headedness, ability to plan ahead, and the ability to come up with creative ideas and think outside the box are what make him a great tactician. He is not an extrovert or loud person. When he was suddenly thrown into a leadership role that involved being in the spotlight, speaking in front of people and ordering people around constantly, he got quite anxious and momentarily froze up. Armin has shown great investment in humanity's future, and is always striving for and thinking about how he can change things for the betterment of mankind. Armin is also good at thinking on the fly and improvising; when he noticed that the ultimate plan of both Zeke and Yelena seemed to go against how Eren viewed the world, he kept this to himself and quickly began to act in a manner that would make Yelena and the Yeagerists believe he also was driven by their cause.

Armin's hard and cruel life has caused him to have certain beliefs about how the world works. Armin believes that in the cruel world in which they live in order to surpass monsters, accomplish goals or make a difference, one must be willing to sacrifice anything, including their humanity. Armin admires strong leaders such as Erwin Smith, Darius Zackly, Ian Dietrich, and Dot Pixis for their ability to sacrifice themselves and their humanity in order to achieve their goals. He believes that tactical decisions should be based on logic rather than emotions, and becomes noticeably affected when others (primarily Eren) do the opposite.

Even though Armin makes calculated decisions, he is also a very emotionally sensitive and empathetic person. Due to Armin's kind heart, he faces conflict in his mind with his belief that he has to force himself to throw away his humanity. For example, Armin killed a person to save Jean as it was the logical thing to do; however, he became very emotionally upset afterward. This, in conjunction with the fact that he is hard on himself whenever he does something wrong, means that he is yet to completely throw away his humanity. Armin's most consistent traits remain his kind heart and keen intuition, making him often concerned with the group's morality. Even when killing multiple Marleyan soldiers and civilians, Armin emerges from his Titan in tears.

Despite this, Armin strongly believes that morality is relative and that there are no universal laws of good and evil. Therefore, he has a distaste for the terms 'good person' and 'bad person', since no one could be either good or bad to everyone. This makes him willing to concoct underhanded, morally questionable plans that shock some of his comrades. Notably, both Mikasa and Eren, his best friends, show no hint of surprise at this ability of his, with the latter even commenting that he had always known Armin was capable of it.

History
Armin originally lived in the Shiganshina District of Wall Maria. After his parents were executed for attempting to escape the Walls, he was left to live with his grandfather.

One day, after the latest in a series of beatings by bullies, Armin sat against a building, crying. Another boy, Eren Yeager, appeared around the corner with a shady look on his face. Eren asked Armin why he never fought back, and claimed that that was why they treated him like that; he then asked him if he wanted to be on the losing side forever. Armin then claimed that he was not losing by not running away. Eren then asked for his name, and the two began a friendship.

Both Armin and Eren were united together as outcasts from the other children in town. One day, Armin discovered a book belonging to his grandfather, describing the outside world. Inspired by what he read, he showed the book to Eren, who was inspired by Armin's excitement to also aim to one day leave the Walls. Armin would often spend his time enthusing Eren about the outside world, for which he held a passionate curiosity. Reading from his grandfather's book about salty oceans, deserts and other surreal places, Armin expressed a desire to one day venture out and see these magnificent sights for himself. However, his interest in the outside world was met with frequent harassment by local bullies, who regarded him as a heretic.

Fall of Shiganshina arc
In the year 845, Armin would once again find himself cornered by bullies who mock him for his deep curiosity for the outside world. Refusing to fight back, Armin would need to be rescued by the timely appearance of Eren and Mikasa. Later, he and his two friends settle by the riverbank, where Eren broods over his desire to join the Survey Corps. Just as Armin muses how the Walls can not protect humanity forever, the Colossus Titan appears and subsequently breaches Wall Maria as Armin and the others watch in horror. As Titans flood the Shiganshina District, Eren and Mikasa head back home to find their doomed mother. Armin tries to stop them, but finds himself petrified by fear. Unbeknownst to Eren and Mikasa, Armin was the one to locate and inform Hannes to save the two before they get killed by the Titans.

After escaping Shiganshina, Armin's parents were both drafted to help try to reclaim the lands lost after the fall of Wall Maria. However, they, like most who participated, were killed during the mission, and Armin was left an orphan. Despite being told that his parents were participating in a Recovery Operation, Armin knew that his parents and the other civilians had been sent on a suicide mission so that there would be fewer mouths for the government to feed. With no family left, Armin moved into a settlement with Eren until the two of them turned twelve, and were able to join the Military.

104th Training Corps arc
No longer content with sitting by in the face of the Titan threat, Armin decides to enlist into military training along with Mikasa and Eren. He was able to pass the basic aptitude test after some effort, and tried to help Eren with it when he struggled to stay upright. Although high in intellect, Armin was considered weak in physical strength, and did not graduate at the top of the class.

The night after their graduation, and before the trainees had decided on their chosen section of the military, (Military Police, Garrison, or Survey Corps,) Armin sits with Eren and Mikasa to eat, and watches as Eren responds to a taunting Jean by finally deciding to set the record straight and giving a moving speech to the whole of the 104th Training on how he wants to kill the Titans to gain freedom and pursue his dream to see the outside world.

After dinner, Armin finds Eren and Mikasa sitting outside the building and joins them, saying that the party is over and that they should head back to the barracks. Before they do, Eren asks Armin which section of the military he will be joining. Armin sits down and reveals that he will join the Survey Corps along with Eren and Mikasa. Eren questions his choice incredulously, citing Armin's physical weaknesses. Armin affirms his worries by acknowledging that he is physically weak. Eren responds supportively but advises Armin not to follow his own crazy course of action while neglecting his own strong points. Armin responds bitterly, saying that he would rather die than become a burden.

Battle of Trost District arc
Armin is shaken by the news of the Titan attack on Trost. He trembles in fear, realizing how sorely unprepared they are to respond, but Eren manages to shake him out of it. Later, Armin joins Eren's squad in the middle guard of Trost and exchanges confident words with Eren about killing Titans, and soon after departs with Mina Carolina, Thomas Wagner, Mylius Zeramuski, and Nac Tias to their assigned location. Along the way, Thomas is caught by surprise and eaten by an abnormal Titan. Enraged and vengeful, Eren charges ahead of the others to engage the Titan, and Armin and the others follow suit. However, the group is ambushed and torn apart by the surrounding Titans, leaving only Armin and Eren alive, with Eren missing his left leg. Shocked and horrified, Armin is left immobile as a nearby Titan plucks him up and attempts to swallow him. Eren, just barely conscious enough to remember how Armin inspired him to see the outside world, leaps to Armin's aid. Eren hurls Armin out of the Titan's mouth, but is eaten in his place as Armin screams in anguish.

Stuck in a state of shock for some time, Armin is shaken out of it by Connie who questions where the rest of his squad is. Armin suffers a mental breakdown, despising himself for his cowardice that resulted in Eren's death. He leaves to inform the rear guard of what happened, along the way lamenting how the world is and always has been hell. On the way, he encounters Hannah trying to resuscitate Franz. Armin tells Hannah to stop, seeing all too well that Franz is bisected and already dead.

Armin is later confronted by Mikasa above the rooftops with the other stranded trainees. She questions him about Eren's location, but as soon as Armin looks at her with tearful eyes she understands. Armin blurts out the names of all the fallen soldiers in Eren's squad, ending with Eren himself. Despite his clear regret, Mikasa calmly comforts Armin and explains that they must not get emotional at a time like this. Armin follows as Mikasa guides the leaderless trainees to safety, but realizes how she is only masking her distress. When Mikasa carelessly uses up all of her gas, Armin comes to her aid. Soon after, Armin, along with Mikasa and Connie, witness the appearance of the mysterious Titan who only kills other Titans.

With Mikasa's gas is exhausted, Armin provides her with all the remaining fuel and blades he has, seemingly ready to remain behind. Armin requests to keep one blade, implying to commit suicide with it, but Mikasa and Connie refuse to leave him behind. With Trost's military headquarters overrun with Titans, and the soldiers running low on fuel, Armin devises a plan to lure the mysterious Titan towards the HQ to wipe out the surrounding Titans. Once inside the HQ, Armin constructs a plan to eliminate the Titans infesting the supply depot inside. While Armin and several other soldiers act as bait, members of the 104th's top 10 would slay the seven Titans by jumping on them from the rafters. Armin's strategy works, and the trainees kill all the Titans and refuel their equipment. Shortly after, Armin witnesses Eren miraculously emerge from the mysterious Titan's nape, unconscious but alive.

After being recovered, Eren is detained by a group of soldiers who are going to execute him. Armin and Mikasa defend him, as he wakes up surprised and confused. Eren plans to escape over the Walls unless Armin is able to convince the soldiers of Eren's value to humanity. Eren tells him that his quick thinking has saved him and Mikasa before, as he was the one who went to Hannes when Shiganshina was overrun. Armin, more confident than ever, walks into the open and tries convincing the soldiers of Eren's value in humanity's battle against the Titans, citing the many Titans Eren killed in his Titan form. As a soldier, he then passionately declares that he is ready to die for this cause and makes a grand salute. Pixis, noticing his determination and passion, prevents their execution.

Now with a boost in self-confidence, he tells the senior strategists that Eren could carry the boulder over to the hole while other soldiers could lure the Titans towards the Walls. They proceed with the plan. Later, when Eren loses control of his Titan form and knocks himself out, Armin rushes to Eren and lands on his back. Remembering the spot where Eren had risen earlier, Armin stabs into him a little askew so that it would not be fatal, but would wake him up. He reminds Eren of his personal vendetta against the Titans, but Eren only becomes responsive once he reminds him of the world beyond the Walls and asks him to think of the reason he wanted to go out there to begin with. Eren, successfully motivated by Armin's words, carries the boulder and plugs the breach. The newly returned Survey Corps the help mop up the remaining Titans in Trost.

Armin is then present as a witness to the hearing that decides Eren's fate as now-revealed Titan. The trial ends with Eren being placed in the custody of the Survey Corps' Captain Levi. He and Mikasa are then separated from Eren until they are able to join the Survey Corps.

Before the trainees are able to decide their chosen military paths, the news spreads that two captured Titans, Sonny and Bean, were slain, and Armin along with other trainees from the 104th Trainee Squad are called in for inspection. Armin, Annie, and Connie discuss which branch of the military they would join. To the surprise of Connie, Armin declares he intends to join the Survey Corps. Annie compliments Armin on his courage, but states she still wants to join the Military Police and survive. To Annie's surprise, Armin tells her she is also good person because he can tell she does not want them to join the Survey Corps either. She disagrees saying that she is not a good person, because she just wants to assure her own survival by joining the Military Police.

The Female Titan arc
After joining the Survey Corps with Eren, Mikasa and the rest of the 104th's top 10 (excluding Annie Leonhart), Armin participates in the Survey Corps' 57th expedition, venturing beyond Wall Rose. Not long into the expedition, Armin's squad encounters the Female Titan, which is seemingly highly intelligent and has considerable knowledgeable about the Military's formation. The Female Titan kills Armin's entire squad, but spares Armin's life after carefully removing his hood and observing his face. As the Female Titan moves on, Reiner and Jean meet up with Armin and the three pursue the mysterious Titan. Armin suggests the Female Titan, like Eren, is a human-controlled Titan and is likely hunting for Eren. The three attempt to engage the Female Titan and Armin is thrown off his horse, but, yet again, the Female Titan does not kill him. The three manage to distract her for a while, though she immediately make a beeline for Eren's position after warding Armin's group off.

Though they survived the encounter, Armin, Jean and Reiner are left stranded with only one horse, which is only strong enough to carry two at a time. While Reiner is patching Armin up he thinks about the Female Titan sparing him a second time and, given her resemblance and what she appears to know, Armin suspected the Female Titan may be Annie though he keeps this to himself. After being bandaged up by Reiner, Armin offers to stay behind, but luckily Krista quickly arrives with two spare horses in tow.

Reaching the Titan Forest, Armin and his fellow soldiers perch on its many high branches, distracting Titans while Erwin confronts the Female Titan. While they wait, Armin concludes that Erwin withheld vital information from most of the soldiers out of fear of traitors lurking among them. Jean criticizes his commander's actions, but Armin defends Erwin, stating that playing it safe will not bring about change. When the expedition ultimately ends in failure, Armin safely returns to Wall Rose with the remainder of the Survey Corps.

Before the operation in Stohess, Erwin, Levi, and other survivors from the 57th expedition hold a meeting in the old Survey Corps headquarters to confirm the identity of the Female Titan. Armin shares his theory that the Female Titan is Annie.

Some time later, in Stohess District, Armin locates and asks Annie, now a Military Police member, for her help in hiding Eren; they need to flee Wall Sheena to avoid Eren's inevitable execution, and they will need a MP on their side to get through the checkpoints. Although initially hesitant, Annie accepts, and Armin explains that they must smuggle Eren out of Wall Sheena by foot, taking an underground route. As he, Eren and Mikasa enter the underground tunnel, Annie refuses to follow, realizing that Armin has led her into a trap. Armin confronts Annie, asking her why she was in possession of Marco Bott's vertical equipment during equipment inspection. Annie claims that she simply found it, but then admits to have killed the two captured Titans using her own equipment when Armin accuses her of such. Annie questions why Armin did not take action if he was already so suspicious of her, but Armin states he simply could not believe it, and questions why Annie chose to not kill him when she had the chance. Annie is not sure herself, but congratulates Armin on managing to corner her, confirming her identity as the Female Titan.

Armin fires a sound grenade, signalling hidden soldiers to restrain Annie. Despite their efforts, Annie succeeds in injuring herself using a barb hidden in her father's ring, allowing her to transform. Anticipating this, Mikasa grabs both Eren and Armin and takes them further underground as Annie in her Titan form attempts to grab them. Seeing that his strategy has failed, Armin initiates plan B, trying to encourage Eren to fight Annie. Eren tries repeatedly to assume his Titan form, but cannot do so due to his reluctance to fight a friend. Having no other option, Armin suggests he and Mikasa distract Annie so that Eren may safely flee. Realizing that if he does not fight, his friends will surely die, Eren finally transforms into a Titan and fights Annie.

After realizing that she is fighting a losing battle with Eren and the Survey Corps, Annie decides to make her escape by climbing over the Wall. As Mikasa, Hange and, other Survey Corps scramble to catch up to her, Armin realizes that they will not be fast enough and instructs Eren in his Titan form to propel Mikasa up the Wall, so that she can gain enough speed to overtake Annie. Mikasa cuts off the Female's Titan's fingers and Eren pins her to the ground, allowing the other Survey Corps members to extract Annie from the nape of her Titan. When Eren emerges from his Titan form and asks about Annie's fate, Armin informs him that no one knows. He shows him that Annie encased herself in rock hard crystal upon being pulled out of her Titan.

As Eren rehabilitates, Armin takes a moment to rest with the others. Armin informs Jean that Eren's summons to the King were cancelled and that Annie is indeed the Female Titan. She is being detained underground after encasing herself in a crystal to avoid interrogation. Reflecting on the mysterious Titans found in the Walls, Armin observes that for all these years they were being protected from the Titans by Titans. Armin cannot fathom how the Walls were built in the first place, but hypothesizes that abilities like Annie's hardening power were somehow employed.

Clash of the Titans arc
Armin's hypothesis is later confirmed when the rock sample Squad Leader Hange Zoë had picked up from Annie's Titan body matched the properties of the Walls. With this information in mind, Armin and Hange propose a way to repair Wall Maria: Eren use his own hardening ability to mend the breach. Minister Nick informs the group about a girl in the Survey Corps who may know more about the Walls, stating that while he cannot share any more details, she can. Armin and the others immediately recognize the girl in question to be Krista Lenz.

Rescuing Krista, Reiner, Bertolt, Connie and a grievously injured Ymir from Utgard Castle, Armin and the Survey Corps regroup on top Wall Rose. However, Armin shortly after learns of Reiner and Bertolt's secret correspondence with Annie, confirming his and Hange's suspicion that the two are also spies. As Reiner and Bertolt attempt to take possession of Eren, they are attacked and nearly killed by Mikasa, but survive. A horrified Armin is present to witness Reiner and Bertolt's Titan transformations, marking the second and third appearance of the Armored and Colossus Titans, respectively.

Armin is called by Hange to aid Eren as he battles Reiner in his Titan form. Meanwhile the Colossus Titan is kept busy defending himself from the rest of the Corps. Advising Eren to retreat to the Wall, Armin provides Mikasa with his spare blades to support Eren against the Armored Titan. Armin and Hange put their heads together and realize that, in order to move, the area behind the Armored Titan's knees will be unprotected. They thus advise Mikasa to cripple the Armored Titan's knees, allowing Eren to gain the upper hand. However, just as the battle turns in Eren's favor, the Armored Titan lets out a loud wail, signalling Bertolt, who then proceeds to push himself off of Wall Rose and crash down on Eren and Reiner below.

Reiner and Bertolt succeed in kidnapping Eren and Ymir in the chaos, and Armin informs Mikasa after she regains consciousness that five hours have already passed since then. Mikasa despairs at the news, but her and Armin's determination are revived upon hearing a rousing speech from Hannes. Joining a force comprised of Survey Corps reinforcements, Garrison and Military Police soldiers all led by Erwin, Armin and the others begin pursing Eren and his kidnappers. Before setting off, Armin implores Krista to stay within the Walls, but she insists on joining the effort.

As Armin and the others reach the Titan Forest where Reiner and Bertolt were resting, they are beset by Titans. Entering the forest with their vertical equipment, Armin's team encounters Ymir in her Titan form. Armin notices Ymir suspiciously surveying everyone and neglecting to attack anyone. His suspicions were confirmed when Ymir suddenly captures Krista and escapes, realizing that she has sided with the traitors.

Reiner transforms into his Titan form and flees the forest with Bertolt, Ymir and a restrained Eren in tow. Pursuing on horseback, Armin notes that while the Armored Titan is slow, stopping him will be difficult due to Reiner not shedding his joint armor. Eventually, Armin and his fellow trainees succeed in latching onto the Armored Titan where they implore Bertolt to surrender Eren. Just as Bertolt suffers a breakdown, Armin and the others are forced to briefly retreat when Erwin charges into the fray, followed by a horde of Titans.

The mass of Titans behind Erwin attack the Armored Titan, slowing him down to a crawl, and Erwin leads his forces into the chaos, seizing the opportunity to rescue Eren. Unfortunately, Erwin is bitten and carried off by a Titan along the way, but Armin remains focused on the mission and joins the second attempt to retrieve Eren. Using his equipment to climb onto the Armored Titan's head, Armin confronts Bertolt, purposefully taunting him with lies that Annie is being tortured while he and Reiner save themselves. Enraged, Bertolt charges at Armin, but is intercepted by a grievously wounded Erwin who slashes Eren off of him. With Eren secured, Erwin's forces retreat, but their escape is cut off by Reiner who tosses Titans in their way.

Armin is horrified by the risk Reiner is taking, seeing that Eren could easily be eaten. In the struggle, Eren and Mikasa are knocked from their horse, and Jean is incapacitated as he and the others rush to assist them. With nowhere to run, Armin drags Jean towards a small cluster of trees and prepares to face an advancing Titan with only one sword. He looks to Eren and Mikasa, seeing them in just as desperate a situation. The friends exchange teary-eyed glances, preparing for the end. However, Armin is saved when Eren's "Coordinate" power suddenly activates, causing the Titans to attack first the Smiling Titan and then the Armored Titan. This allows Armin to retrieve a horse, and carry a wounded Jean to safety. They retreat from the battlefield, mourning the loss of Hannes, who died in the chaos, and remembering their childhood with him.

The Uprising arc
Returning safely to Wall Rose, Armin and Jean agree that the 104th have been exceedingly lucky. As the wounded are taken away Eren grimly remarks that he got captured again and asks how many people got injured because of him. Armin tries to soften the situation, saying that they experienced no losses on the way back, with the Titans ignoring them and only attacking the Armored Titan. He mentions the Female Titan being able to draw other Titans toward itself, and states his and Jean's theory that Eren had controlled the Titans this time.

Some time later, Armin is seen helping Jean and Sasha carry food into their new relocated house. Armin mentions that there are food shortages all over, and if they lost their current provisions then they would surely starve. After the food is inside, Sasha asks why they bought so much food when they could just easily hunt for it in the woods. Armin reminds her that hunting is prohibited in the area.

Eren appears and reminds them all the importance of cleaning off their shoes before coming in causing Jean to yell at him and remind him that he is not his mother. Mikasa and Historia come back after chopping wood, much to Armin's shock, as he tries to remind her that she is not a wild animal and should not be moving around yet. As the group banter and argue, Sasha speaks on how this is like all of them being trainees again. Armin is quick to remind everyone that protecting Eren and Historia is an important task. He then asks why they were selected for Levi's new squad, commenting on the fact that many veterans are still alive. Eren tells them all to finish cleaning before Levi and Connie return.

The group then reunites with Levi and discuss Armin's idea of sealing the hole in Wall Maria using Eren's Titan hardening abilities. Hange informs them that Nick was found dead that morning, tortured and murdered by members of the Military Police's First Interior Squad, and Armin wonders how much he would have revealed, though Levi guesses he did not reveal anything. He also was there when Historia told about her past, prior to her enlistment in the Survey Corps.

During a failed test for Eren to harden his Titan form, Armin was present. He was also present when the group read Erwin's orders, looking shocked at the sight of it. During their first official operation, Armin serves as a body double for Historia, and is eventually captured by the organization that wishes to take possession of Eren and Historia. While being held captive with Jean, who was serving as Eren's double, one of the men harasses him, asking over and over to hear Armin's voice, as he was suspected to be Historia. Armin displayed great discomfort at this, being driven to tears from it.

Armin is seen still tied up with Jean as the men issued to take Eren and Krista arrive, observing them silently before they are attacked by Mikasa and Levi. He and Jean then race from their positions, revealing that they were pretending to be tied up, and tie the beaten men up.

After the men are successfully detained and questioned by Levi and Mikasa, Levi orders Armin to fix the mouth gag on the man who originally harassed Armin. As he began to fix the gag, the man mentioned that he heard Armin was actually a boy. He then tells Armin that he used to be normal, but Armin now turned him into this and then tells him to do something about it. Armin appears shocked, unresponsive to the man. Jean then tells Armin to leave the work to him.

After the Survey Corps capture two First Interior Squad officers, Armin is seen with the rest of his friends talking about how they might be able to pull off a successful coup d'état. He is present when the Survey Corps discuss the plan to make Historia ascend as queen.

After Eren and Historia are kidnapped by the First Interior Squad, he is seen at Trost district, preparing with the rest of the Survey Corps to retrieve the caskets in which Eren and Historia are being transported. It turns out to be a trap to lure the Survey Corps, and they immediately try to escape town, with Armin driving a carriage. One female member of the First Interior Squad gets through and tries to shoot Armin, but Mikasa kicks her and she lands on the carriage. She gets up, ignores Jean's threat and knocks his gun away. While she is pointing a gun at Jean, Armin reacts quickly, pulls out his own gun and shoots her in the head. Thus, he helps save Jean. After the SC retreat to safety, he was not able to take the guilt of killing another human being and becomes sick. Mikasa comforts him. Levi tells him that he cannot go back to being the way he was, as his hands are now already dirty.

After the Survey Corps is accused of trying to monopolize Eren's Titan powers, the government begins arresting all members of the organization. Armin and the rest of Squad Levi avoid being captured, and camp out in the woods outside of Stohess. The squad ambushes two MPs, with Armin distracting them as bait. Mikasa and Armin take their uniforms and put them on with the intention of infiltrating the Military Police to find out where Eren and Historia have been taken, but the two soldiers, Marlowe and Hitch do not take their capture quietly, and eventually gain the squad's trust, leading them to a nearby MP checkpoint.

After crippling most of the personnel, Levi and his squad escape with a hostage and interrogate him about Eren and Historia's location. They hear people approaching on foot and prepare for battle. To the entire squad's delight, it is Hange, who informs them that the Survey Corps has been exonerated, and that they have a lead on Eren and Historia's whereabouts. As the group begins to ride for the Reiss chapel, Armin silently wonders who Eren had inherited his Titan from.

Armin plays a pivotal role in planning out their fight with the remaining Interior MP forces stationed at the chapel. The plan is to take cover under the smoke by igniting gunpowder inside barrels and also by utilizing their smoke signals, as it would be advantageous for them with their lower numbers. Armin is one of the soldiers who fire flares to provide cover. Hange is injured during the fighting and Armin is left behind to take care of her.

Armin and Hange meet up with Levi's squad after they escape the cavern and follow Rod's Titan as it makes its way to Orvud District, meeting up with Erwin's forces en route. At dawn, the Titan arrives and Eren, Mikasa, and Armin assemble a stack of barrels filled with gunpowder at Hange's direction. Eren sees a group of kids below and remarks on how they remind him of himself and his friends on that day when the Colossus Titan first appeared. Armin agrees, but reminds Eren that there is a difference this time, with them being ready to face the threat. To Armin's surprise, Eren suddenly begins punching himself to bring himself back to his senses.

Return to Shiganshina arc
After Historia has been crowned queen, he is seen helping out at the farm for the orphans and people in need from the Underground.

He and the rest of Survey Corps prepare for the upcoming mission for retaking Wall Maria and have meals together. Before they set out for the mission, he reminisces their childhood with Eren and Mikasa, and enthusiastically talks of being able to see the outside world, stating that they should start by visiting the ocean.

During the journey towards Shiganshina, he notices Eren seemingly in fear and doubt and encourages him, reminding him of their collective dream to see the outside world, making him feel better.

After arriving in Shiganshina, Armin and his squad take up positions atop Wall Maria. As the rest of his squad proceeds to the breach in the wall, Armin notices the remains of a campfire nearby and alerts Erwin. On Erwin's orders, Armin proceeds to the foot of the wall where he finds evidence that three people had been camping out atop the wall. He returns to Erwin to inform him of what he has found, and the two of them deduce that there is likely a fourth person accompanying their enemies who warned them of the corps' approach so that they could hide. To Armin's surprise, Erwin gives him command of a team of soldiers, and orders him to find where their enemies are hiding.

As he is searching, Armin recalls the fact that the Walls are filled with Titans and deduces that there might be hollow spots where the Warriors could be hiding. He orders his team to search the wall for hollow areas and despite their initial skepticism Erwin orders them to obey. One soldier stumbles across a hollow spot and from within emerges Reiner who immediately kills him. He prepares to attack Armin, but Levi swoops down and intervenes. Armin is once again entrusted by Erwin to help direct the battlefront where they would fight the Armored Titan. He relays Erwin's plan to take on the Armored Titan to squad leader Hange.

After they blow Reiner's head off, he laments that with their abilities they could not afford any negotiations. However, Reiner's Titan form gives out a roar and Armin immediately realizes that it might be a signal to call Bertolt. Sure enough, he sees a barrel hurling towards them from the sky, thrown by the Beast Titan. With the Colossus Titan coming from above, Armin and the soldiers try to flee from the scene, but turns around when he realizes Bertolt had not transformed yet. Instead of attacking Bertolt, Armin reminds everyone that they should make a last attempt to negotiate with him.

Bertolt shares a bitter conversation with Armin, claiming that it was he who decided to come up with malicious schemes in order to conquer humanity. Thinking fast, Armin throws Annie's name in the conversation, declaring that only Bertolt is capable of saving her from the Military Police. Bertolt coldly dismisses Armin's remarks and approaches him with his blade ready. He reveals to Armin that he saw through his plan long ago, but he just wanted to ensure that he is to kill them properly. A confused Armin asks why Bertolt thinks that all humans are descendants of evil, but Bertolt shrugs the question off and continues to advance towards him. Before he can reach Armin, however, Mikasa attacks Bertolt from behind, forcing him to defend himself and then make a quick escape to find Reiner. Armin attempts to chase after Bertolt, but Mikasa stops him, warning of Bertolt's intentions to transform. Sure enough, Armin soon feels an immense explosion resonating throughout the district, signifying that Bertolt has taken his Titan form.

Armin witnesses the Colossus Titan destroy the district. When Jean asks Armin for a plan, Armin advises to tire out the Colossus Titan because it cannot climb over the Wall. Jean interrupts Armin's plan, deeming it too dangerous to risk leading the Colossus Titan to the Wall due to Erwin's group being on the other side. Jean concludes that a tactical approach is the logical plan, however they have limited supplies, such as their vertical equipment. Armin realizes that this is their only chance of attack solely counting on their current manpower. Jean asks Armin for the next phase of his plan, but Armin is out of ideas and requests Jean to take over.

Following Jean's orders to reach the river, Armin climbs onto Eren, who stays out of sight from the Colossus Titan. Jean tells Armin that he might be able to get a grasp of their situation, however in the end he would have to rely on Armin's planning for it to work. Armin, incredibly frantic, is reprimanded by Jean to stop. He is tasked to observe the Colossus Titan from the farther back while Eren attacks him to keep him from reaching the Wall.

Armin looks on in horror as Eren is kicked to the top of the Wall by the Colossus Titan. As Mikasa retreats from a burst of steam from the Colossus Titan, Armin notices that Mikasa is hurt. She asks him if he has come up with any other ideas, but he has not. Before they can come up with any other plans, Armin looks on in shock to find the Armored Titan still alive and ready to battle once more. After some consideration, Armin finally comes up with a plan; he explains to the group that the Colossus Titan has become thinner compared to when it first transformed, meaning that it will soon run out of energy. Armin tells Jean and Mikasa to go after the Armored Titan, while he and Eren will take on the Colossus. Reminiscing the days when he and Eren promised each other that they would one day see the ocean, Armin comments that if this plan fails, he will never get to see it. Armin then stabs Eren's Titan form, telling him to wake up. Armin succeeds in waking Eren and explains the plan to him, telling him to go through with the plan no matter what. Eren hesitantly agrees.

In accordance with Armin's plan, Eren lets his Titan form fall to the ground in front of the north gate, seemingly defeated. Armin stays on the Wall, pretending to be surprised. As Eren's Titan form falls he secretly hardens his body and escapes through the nape, fleeing from the scene. Armin stays to face the Colossus Titan, thinking about how Eren will carry out his dreams to see the ocean if this plan takes too long. Grappling to the Colossus Titan's teeth, Armin succeeds in getting Bertolt to emit a massive wave of heat and smoke. Armin remains grappled as the heat begins to hinder his breathing, but he remains resolute in his decision. Bertolt begins to pity Armin's selflessness and emits a massive wave of searing heat and steam to kill Armin quickly.

As Armin's flesh, skin, and clothing begin to burn off, Armin chooses to remain grappled, realizing that he is about to die and that Eren must see the ocean in his stead. Soon, Armin's grip on his sword hilt is broken, sending his charred body flying to the rooftops below. As Bertolt inspects Eren's hardened Titan form, Eren uses his maneuver gear to get behind Bertolt, slicing him out of the Colossus Titan's nape. As Eren stands on the roof by Armin's body, he sorrowfully says that Armin was always the bravest of his comrades.

As Eren mourns Armin's sacrifice, sadly looking down upon his body, Eren hears Armin breathing faintly and urges Levi to use the Titan injection on Armin. Levi agrees at first, but then reconsiders when he discovers that Erwin is still alive. After a tense altercation with Mikasa and Eren, Levi, remembering Erwin's final moments, decides to use the serum to save Armin and transform him into a Pure Titan. Armin's Titan form eats Bertolt who had been left behind on a rooftop for that purpose. After eating Bertolt, Armin emerges in his human form, unconscious and fully healed, having acquired the power of the Colossus Titan.

While unconscious, Armin has a nightmare about Bertolt. When he comes to atop the Wall, he notices Sasha lying next to him and notices her severe injuries. He sees Eren heading toward him and he hugs Armin when he reaches him, relieved that he is awake. Having lost his memories of the events immediately before his transformation, Armin is confused, so Eren informs him on the recent events that happened. After hearing this, Armin acknowledges that he ate Bertolt. He feels sick and asks his comrades why they did not save Erwin instead of him. Levi states that Armin should not let others regret their decision on choosing to save him, including himself. Hange claims that Armin and herself will have to prepare for whatever comes next and that they are in similar situations. Hange then says that she, Levi, Eren, and Mikasa will be heading out while Armin and the rest of the soldiers remain atop the Wall resting and keeping watch.

After their mission, Armin returns to Wall Rose with the remaining members of the Survey Corps.

While Eren and Mikasa are imprisoned for having violated military law, Armin stays with them. On one occasion, when Eren wakes up screaming and confused, Armin reminds him why he was in jail. He is confused by Eren's choice of language at this time. For the rest of their time in jail, Armin helps Eren validate the three books discovered in the Yeager family basement by comparing them with Eren's memories. Here, Armin recognizes that his lifespan, like all previous holders of a Titan power, has been shortened due to the Curse of Ymir.

After visiting Historia in Trost, Armin attends a meeting, along with the rest of the Survey Corps, to discuss how the Wall people should progress following Shiganshina. He stays silent, seemingly until the end of the meeting, when it is decided to make the basements discoveries public knowledge.

Later on, Armin joins the Survey Corps to be honored for their bravery and success in the Battle of Shiganshina District. Before the meeting begins, Armin brings up the matter of the Titan injection with Floch. Floch candidly states that Erwin was the better choice for the serum, and that all other people reading the report agreed. After a short argument between Floch and the 104th Survey Corps members defending Armin, the group is called into the hall to begin the ceremony. Armin receives a medal along with the rest of the Survey Corps.

One year after the Battle of Trost District, the Survey Corps embarks on a scouting mission beyond the Wall. After a long journey on horseback, Armin fulfills his dream when the Survey Corps reach the ocean. Down at the beach front, Armin seems joyful at having accomplished his dream, yet when attempting to speak about the ocean with Eren, he is only reminded of the threat lurking on the other side of the ocean.

Marley arc
One year after retaking the territory within Wall Maria, the military of Paradis discover a Marleyan survey ship near the island. Armin goes with the Survey Corps to intercept the forces and witnesses Eren's Titan upend the ship and forcing it on the shoreline. After two spies, Yelena and Onyankopon, rebel and shoot the captain of the ship, Armin watches from afar the two meeting with Hange and Levi. He notes that it is fortunate they get the chance to learn more about the people of Marley but is put off by Eren saying Paradis needs to strike hard at Marley.

Over the next three years, Armin works with Eren to destroy more than thirty additional ships sent to Paradis by Marley. During that time, Armin notes that people from both Paradis and Marley are learning more about each other and that the citizens are just like them; not all the people of Marley were enemies and are open to working together for a better future. Armin takes part in a meeting where Onyankopon describes that he is from a different country and race than the Eldians; Armin asks him who made them all and is told the same one who made the people of Marley, the Subjects of Ymir and who granted the power to Ymir herself; a God.

While at a shooting range with Eren and Mikasa, Armin is proud to see both sides cooperating and interacting with one another. He notes that the port at the harbor will be done soon, and believes that Eldians and Marleyans will soon be able to fully cooperate and work together without any tensions on either side. Eren then asks if he could see anything from Bertolt's memories, and Armin says nothing that could help them. He looks to Eren and asks if they should go along with Yelena's plan, questioning if there is another way. Mikasa asks if there is a problem and Armin poses that they gather and discuss their misunderstandings with Marley and the other countries before having to result to violence. Eren abruptly cuts him off and claims the world still sees them as monsters, feeling that it would be pointless. Armin reasons that they merely need time and Eren again insists that Paradis must make the first strike against Marley to buy them the needed time. While aboard a train, Armin overhears the others discuss who should inherit Eren's Titan abilities after his tenure expires in five years; he silently reflects on how Eren valued each one of his friends and that due to wanting them all to live for a long time, he would not accept any of them as his successor.

Armin is one of several Survey Corpsmen who journey to Marley's mainland to meet with Kiyomi. During their meeting, Armin is distressed to hear that it will be exceedingly difficult for the Azumabitos to convince the world's powers to begin accepting Eldians once again, noting that the only other option would be to take advantage of Historia. Eren leaves in the middle of the meeting, and Armin and the rest of the 104th graduates go to look for him. They find Eren and Mikasa speaking with a family living near the Azumabito estate and agree to eat dinner with the family, spending the night drinking and carousing.

The soldiers sit in on a hearing between politicians to discuss Eldian mistreatment. They are horrified when the speakers begin calling for the hatred being shown towards Eldians to be redirected towards the Eldians living on Paradis. As they are listening, they fail to notice Eren quietly depart from the meeting.

Eventually, the Survey Corps receive a letter from Eren informing them that he will be launching an attack on Marley against their orders and coordinate a rescue. Armin is tasked to infiltrate the Marley harbor near the internment zone at Liberio. At the time of the Survey Corps attack, Armin sits in a fishing boat within the harbor as the Marley armada approaches. When navy soldiers call out to him, Armin stares at them before unleashing an explosive energy burst, transforming into the Colossus Titan. This explosion destroys the battleships coming to Liberio's reinforcement. In his Colossus Titan form, Armin looks down at the destruction that he has caused, noting sadly that Bertolt likely witnessed the same scene when he attacked Shiganshina District. He then exits from his Titan form and uses his vertical maneuvering equipment to make his way onto an airship that has been occupied by the Survey Corps' forces. He discusses with Hange about entering Liberio by using the low-level airspace, moving alongside the lights placed earlier by the Survey Corps in order to collect their troops; a very dangerous mission as everyone has only one chance to board the ship, and the ship can also be shot down. Hange questions whether Armin is possessed by Erwin's ghost to come up with such a risky idea, but Armin replies that he wishes this was the case if that could give them strength; but at that moment, if they are unable to retrieve everyone and Eren, they will have no future.

Armin helps Eren onto the airship, and subsequently stops Mikasa from responding after Levi kicks Eren and has him detained. The group goes to another room in the airship, where they hear an uproar through the door shortly after. Jean then comes through the door with two restrained children, explaining that they had boarded the airship and one had shot Sasha, who was unlikely to survive her injury. Armin and Mikasa rush out of the room to see her, but Sasha dies shortly afterwards prompting the two to break down in tears.

Returning to Paradis, Armin is left distraught by Sasha's death, and by the knowledge that it was Eren's rash actions that led to her death as well as the deaths of numerous innocent civilians. Following Sasha's burial, Armin visits Annie's crystal to ponder Eren's unpredictable behavior. Reflecting that despite his desire to understand Eren more than anyone (even Mikasa), Armin admits that he no longer can. He notes that due to the civilian lives that were lost as a result of the Survey Corps' actions, Armin laments the lost opportunity for peace; however, Armin does try to justify to himself that their actions (and his own) were necessary to keep Marley at bay for the time being. As he finishes ruminating, he pleads for Annie to respond to him in some way.

War for Paradis arc
Later, he meets with Mikasa, Jean and Connie and reflect on how the Anti-Marleyan Volunteers were arrested even though they helped give Paradis aid. Despite agreeing with Jean's disbelief, Armin reflects that it was already decided while they were in Marley. He listens to Connie and Jean accuse Eren of sending them to fight despite supposedly valuing their friendship and is stunned to hear Connie's remark that Eren laughed after hearing Sasha died, instead of expressing sorrow or anger. Armin recalls how Eren will be in control of the Founding Titan during 'The Rumbling' and resolves to arrange for them to talk with Eren to determine which side he is on. Accepting that they must be prepared to kill Eren if he switches sides, Armin proposes a worst case scenario to have someone transformed into a Titan and obtain Eren's powers before the end of his tenure. Mikasa protests this but Armin repeats that they have to discuss with Eren and determine first if he is still on their side.

Armin later attends to the questioning of a group of four Survey Corps members who had spread the word that Eren had been imprisoned after the Raid on Liberio. Afterwards, Armin goes back to the holding area underground where Annie's crystal is located. He goes over and touches it to try and access any information they can use. Suddenly, he hears Hitch behind him telling him not to touch Annie's crystal. Armin stammers that Titan memories can be transferred via touch and was merely trying to see if he could see anything; he pleads with Hitch not to ban him from visiting Annie. They walk back outside and Hitch hands Armin a newspaper, reporting that people are distrusting the Survey Corps even more. Armin agrees, but insists they must hurry and figure out Eren's true motives before it is too late. Hitch goes off to help several other members to keep the protesters away while Armin goes with Mikasa to a meeting scheduled with Darius Zackly.

He is shocked to hear Darius refuse their request to see Eren at this time. When Armin asks why, both of them are stunned when Darius reveals to them the belief that Eren may be under the control of Zeke. Armin insists they can be useful in figuring out Eren's motives, but Zackly still does not allow it and dismisses them. Moments after leaving, an explosion occurs and Mikasa grabs Armin and protects him from the blast. Armin and Mikasa are horrified to see both the mangled corpse of Darius, blown apart from a bomb planted in his office, and the crowd of protesters seemingly in support of the act.

During a meeting going over the attack, Armin recalls seeing Zackly's chair in his office and that Darius mentioned a group of recruits had brought it to his office. Having seen a group of Survey Corps recruits leave as they arrived at headquarters, Armin pieces the two together just as word reaches to them that Eren has escaped confinement. At a loss for words, Armin goes with Mikasa, Hange, and Onyankopon to figure out what to do next.

Armin attends another meeting to discuss how the military will deal with the Yeagerists. Pixis instructs the military to secure Historia and Zeke, and tells Armin that his defenses with the power of the Titans must be stronger than ever. Recognizing Pixis as the acting Commander-in-chief, Armin asks him if he has any long term plans. He is then surprised by the Commander's reply that they should surrender to Eren and begin negotiations. After the meeting's conclusion, Armin leaves with the other Survey Corps veterans to visit a suspicious restaurant employing Niccolo.

After arriving at the restaurant to question Niccolo, Armin and the others wait in a backroom for him to finish cooking. A short while later, Armin opens the door to the dining hall after hearing a commotion, and sees Niccolo attacking the run-away Warrior candidates. He quickly calls the others into the main room, but is kept at bay due to Niccolo threatening one of the candidates. Eventually, when Mr. Blouse calms the situation down, Armin and Mikasa bring the Warrior candidate who had killed Sasha into the backroom, allowing the Blouse family to weep. As Armin talks with Gabi, he remarks that her mentality is very similar to how Eren used to act; just then, Eren arrives unexpectedly and shocks both Mikasa and Armin. Armin tries to speak with Eren, but notices his palm is cut and bleeding; seeing Eren's intent forces both Mikasa and Armin to comply with Eren's demands. They sit down at the table with Gabi, and Armin asks Eren if Floch and the other Yeagerists are there to harm the others; Eren merely says they are simply being moved to another location. Armin asks Eren if Zeke and Yelena have swayed him to their cause and what drove him to attack Marley on his own. Eren merely responds that he is free at last to do whatever he pleases and questions if Armin is still visiting Annie, greatly shocking Armin. Eren tells Armin that if memories truly play a part in forming who a person is, that means Bertolt's memories have become part of Armin; he calls Armin a soft and useless pawn of the military.

As Eren reveals Mikasa's heritage has been the sole reason she has stayed by his side, Armin notices that Mikasa is visibly suffering from this and orders Eren to stop; after Eren calls Mikasa a mindless slave, Armin goes to attack him only to be blocked by Mikasa: this stuns and horrifies both of them. Armin is still able to punch Eren, who takes the blow and throws him against a shelf. Eren mocks Armin's fighting abilities and effortlessly beats him. As Eren orders his followers to take them away, Armin bitterly asks if Eren wanted the freedom to hurt Mikasa and calls Zeke a piece of shit while claiming Eren is the true slave; this angers Eren and has them all taken to Shiganshina District. Armin is then confined alongside those recently captured by the Yeagerists.

Sometime later, Connie asks Armin to use his Colossus Titan to escape but the notion is rejected due to the Titan's destructive power. Jean would then pry into the details of Armin and Mikasa's encounter with Eren but Mikasa idly brushes off the question. Their conversation is halted when Yelena arrives and subsequently surprises everyone by shooting Griez for insulting the Eldians. As Yelena explains Zeke's true motives, Armin begins to cry claiming he is moved by Yelena's noble intentions before a soldier arrives to inform them about the infiltrators. The Survey Corps members and other prisoners are subsequently alerted by the rattling of the walls and Armin remarks that the Titans have started moving. Several minutes later, Onyankopon arrives and unlocks the cell door, asking they help Eren. As Connie slams him against the wall, Armin tells Connie to let him go and hear his side before doing anything.

After Onyankopon continues to plead his innocence and that he did not desire to eradicate the Eldian race, Armin recalls the time when they conversed about how someone thought it would be interesting to have different kinds of people in the world which includes Eldians. Helping him to his feet, Armin asks Mikasa if she wants to help Eren; after getting a reluctant response, Armin mentions how he believes what Eren said to them was nothing more than just a lie to make Yelena and Zeke believe he was on their side. He continues on by stating that when the Rumbling is activated, the other nations will be observing from Marley and see that the few hundred Titans within the Walls awaken will prevent them from attacking Paradis Island. After the other captured soldiers are released, Armin goes to suit up with Mikasa. As Mikasa continues to believe what Eren said about her to be true, Armin brushes her concerns aside and states that Eren used the excuse about her headaches to make the lie more believable.

As they reach the roof, they spot Yelena staring up at the destruction overhead. As Yelena mentions how Zeke was able to defeat both Hange and Levi, Armin continues to play along and rallies the others to join the Yeagerists in saving both Eren and Zeke in order to save the world. Armin then turns around to see Yelena peering down at him intensely and then asks for them to save Eren. As the Survey Corps try to get close to Eren, Armin and the others notice Zeke getting shot atop the Wall and falling back down to the ground. As Armin decides him and Mikasa need to target the Cart Titan, they both get shot at by several Marleyan soldiers. After Connie launches a Thunder Spear and saves them, Armin overhears Commander Pixis and Nile Dok organizing the ground soldiers; he agrees with the plan and has Mikasa go with him to get behind the enemy.

As they travel through the air, Armin and the other Survey Corps soldiers hear Zeke scream and notice several flashes of light throughout Shiganshina District; they realize that the affected soldiers have been turned into Titans and their task will now be even harder. Reaching the Cart Titan, Armin fires a Thunder Spear at it and destroys the artillery cannon. As Pieck and the soldiers try to kill Armin, Mikasa swiftly kills the two soldiers. Armin then angles around Pieck as Mikasa aims to strike the Cart Titan.

As they are fighting, Armin and Mikasa are caught off guard as Wall Maria begins to crumble, and are horrified to see the Titans inside emerging. As the Wall Titans begin to march, Armin assumes that Eren is using the Founding Titan to send the Wall Titans to attack the forces amassing in Marley to attack Paradis. However, he is perplexed to see that all of Wall Maria is crumbling, noting that an attack on Marley should have only required the Titans contained in Shiganshina's outer Wall. He is interrupted by Eren, who begins speaking to all Subjects of Ymir through the Founding Titan. To Armin's horror, Eren declares that he is going to be using the Founding Titan to completely exterminate all life outside Paradis Island.

Armin and Mikasa regroup with Jean and Connie, who have Falco with them. Although Jean half-heartedly tries to justify Eren's plan, Armin is firmly opposed to the genocide Eren is about to commit. Noticing their fellow soldiers being attacked by Titans, Armin and Jean go to help them but Mikasa points out that they need to deal with Falco. Jean suggests feeding the boy to one of the Titans while Connie argues that his mother should be allowed to eat Falco. Armin does not want to sacrifice Falco at all, arguing that killing him will only breed more animosity with the Warriors, but Connie angrily points out that Armin is being a hypocrite for not allowing his mother to be saved the same way Armin himself was saved. The group is attacked by a Titan, allowing Connie to flee with Falco before the group can stop him.

The group returns to the military headquarters where they rally the soldiers trapped inside to help them kill the Titans which have amassed around the building. After clearing out the first wave of Titans, Armin's group lies in wait at the building while more soldiers lead the remaining Titans to the building to be killed. Armin recognizes one of the Titans to be Pixis and quickly mourns the commander before executing him.

After the fighting, Mr. Blouse brings Armin and Mikasa to meet Gabi, who begs them to return Falco to her. Armin explains what has happened to Falco, and Gabi desperately tries to argue that Eren can return Connie's mother to normal with the Founding Titan, but Armin points out that Eren would likely have used such an ability on the Titans in Shiganshina if he could. Gabi frantically argues that Eren should be able to, as he was able to undo the Armored Titan's hardening abilities. Hearing this, Armin recalls Eren's proclamation that he has undone all hardening and realizes that Annie's crystal must have also been affected.

Armin decides to depart for Ragako with Gabi to try to catch Connie. Mikasa tries to convince him that it is futile, but Armin is determined to at least try to preserve any chance of making peace with the Warriors. Mikasa attempts to ask what they should do about Eren, causing Armin to lash out at her. Immediately regretting his actions, Armin laments that he was the one saved in Shiganshina, not Erwin, as Erwin would have been able to handle the current situation. Armin departs for Ragako with Gabi soon after.

Armin and Gabi arrive at Ragako as Connie is preparing to feed Falco to his mother. When Armin fails to talk Connie down, he reflects once again that Erwin should have lived instead of him and chooses to sacrifice himself to save Connie's mother. However, he is saved from being devoured by Connie who explains that he has come to realize that his mother would not want someone else to be sacrificed for her.

After returning to Shiganshina, the group takes time to rest and eat. As they are eating, Armin and Connie discuss the possibility of Annie having escaped her crystal. As they are speaking, they realize that Annie is sitting next to them.

The group and Annie make a plan with Jean, Mikasa and Pieck Finger to escape Shiganshina. After receiving a signal from Jean to leave the military headquarters, Armin departs with his comrades. On their way out of Shiganshina, they pick up Reiner.

The group travels to Paradis' harbor with the intention of using the Azumabito clan's airship to pursue Eren, but find that it is already occupied by Yeagerists. The group gears up for a possible engagement, but Armin and his friends are reluctant to fight their former comrades. Their discussion is interrupted by Hange who announces to everyone's horror that Eren has apparently already reached Marley. A desperate Magath apologizes to the Eldians for how he and the rest of Marley treated them and begs them to cooperate with him.

As part of a plan to trick Floch into turning over the Azumabito mechanics, Armin and Connie ride into the harbor and tell Floch that they have been pursuing the Cart Titan ever since it devoured Jean and Onyankopon. They tell Floch to send the Azumabito mechanics to help them start the ship so they can continue their pursuit and proceed to the ship without waiting for his response. They are stopped by Daz and Samuel and, seeing that the plane has been rigged to explode, demand that they disarm it. Daz and Samuel question them about their allegiance and Armin and Connie manage to convince them to begin disarming the bombs on the plane.

As they are waiting for the mechanics, Armin and Connie are horrified to hear gunshots, followed by an announcement from Floch that they and Mikasa are traitors. Daz begins rewiring the bombs on the plane and Armin tries to stop him, only to get shot by Samuel. As Connie wrestles with Samuel, Armin continues to try to stop Daz despite his injuries. Daz tries to shoot him, forcing Connie to kill Daz to save Armin.

High Intelligence
Being physically weak, Armin is rarely assigned to the front lines and rarely uses his vertical equipment for direct combat. Instead, his greatest strength lies in his intelligence - innate abilities of deduction and strategy formulation, be it in a war room or on the fly. But Armin has a keen eye for detail, making him a remarkable field tactician, a trait that distinguishes him among his fellow trainees. His strategies help save his fellow soldiers numerous times and, more remarkably, he played a key role in deducing the identities of all the hostile Titan spies among the 104th Training. Initially, Armin's intelligence was hampered by a severe lack of confidence, but after acknowledging and nurturing this side of himself, Armin's potential as a tactician began to show, and even high-ranking officers took his strategic opinions seriously.

Power of the Titans
Armin gained the power of the Titans, specifically the Colossus Titan, after being injected with the Titan serum by Levi and then consuming Bertolt shortly afterwards. Like any other inheritor of the power, this grants him the ability to recover from most lethal injuries (unless his weak spot in the neck is damaged without transferring his mind to the rest of his nervous system) and to freely transform between Titan and human forms while retaining his intelligence.
 * Explosive Transformation: Armin can unleash a massive explosion when transforming into his Titan. He used this to great effect during the Raid on Liberio, devastating the Marleyan navy with his transformation.
 * Enhanced Strength: Armin's Colossus Titan possesses immense size and strength, capable of crushing entire battleships underfoot.
 * Regeneration: Like all the others with the Power of the Titans, Armin had the ability to regenerate any injury he may suffer. Armin began to heal an injury given by Samuel.

Relationships

 * Eren Yeager - Eren was Armin's best friend from childhood. As children, Armin looked up to Eren, as he was always there to protect Armin from bullies regardless of the odds. Armin made Eren enthusiastic about the outside world, and together the two would dream of venturing beyond the Walls. Initially, Armin felt inferior to Eren, ashamed of being in need of his protection, and lacking the courage his friend boasted. Despite this, Eren gave Armin the confidence to begin using his strategic mind to its full potential, reminding him of the times his reasoning and quick thinking saved them. However, their difference in opinion on how to react to the Marleyan threat and the death of Sasha Blouse in the Raid on Liberio causes friction to develop between them. At this point, Armin admits he no longer understands his childhood friend. After Eren joins the Yeagerists, Armin physically attacks him to stop him from hurting Mikasa and calls him out on whether the freedom he wanted was the freedom to hurt her. Later, Armin correctly deduces that Eren is only pretending to go along with Zeke's plan, realizing that Eren is just using Zeke to unlock the Founding Titan's powers. When Marley begins a counterattack for the Raid on Liberio, Armin chooses to stand with and aid Eren, showing that despite their differences their friendship has not truly been destroyed.
 * Mikasa Ackerman - Mikasa is a close friend of Armin's. Whenever Armin got into trouble with local bullies, Mikasa would always come and save him. Armin looked up to Mikasa's strength and courage and felt inferior to her. Mikasa, however, believes in Armin's abilities to reason out the best solution in a dire situation and trusted him deeply. She was responsible for boosting Armin's confidence and shaping his character. After the Raid on Liberio, the two rely on one another after Eren’s betrayal, Mikasa more so on Armin. Armin understands Mikasa’s feelings for Eren very well and is more conscious of the pain she is in, acting as a source of comfort and reassurance for his childhood friend. He becomes protective of her, to the point of attacking Eren for verbally abusing her, in an attempt to spare Mikasa more grief.
 * Jean Kirstein - While Armin was initially not that close to Jean due to the latter's rivalry with Eren, their relationship has changed considerably since joining the Survey Corps. Armin's growth as a strategist has aligned with Jean's growth as a leader, and the two often share insights or opinions with one another. He risked his own life in order to protect him, when Jean fell unconscious during Eren's retrieval and also killed an anti-personnel squad member to save him.
 * Annie Leonhart - The two share a mutual respect for each other, expressing admiration for each others' hidden qualities. This causes her to hesitate when attacking in her Titan form, a mistake which allowed Armin to discover her true identity. He then uses emotional blackmail in order to lure her into a trap and facilitated her eventual capture. After Armin acquires the Colossus Titan, and therefore Bertolt's memories, he frequently visits Annie in her crystal to confide in her.
 * Reiner Braun - Reiner is shown to have been protective of Armin, helping him during physical training exercises and carrying him to safety during dangerous operations. Armin initially defends him when he was suspected of being a spy, but quickly realizes the truth and provides evidence of Reiner's guilt.
 * Bertolt Hoover - Armin and Bertolt interacted on a few occasions, though Bertolt did consider Armin a close friend. This, of course, soured once Bertolt's true identity was revealed, and he threatened to kill Armin when the latter lied and claimed that Annie was being tortured. He was hostile toward Armin when they faced off in Shiganshina, once again coldly expressing his desire to kill him and all of his friends. He nearly made good on this threat not too long after, as he severely burned Armin with a powerful steam discharge while in his Titan form. Later when Armin was injected with the Titan serum, Bertolt's final moments were daunting, having been devoured by Armin in his Pure Titan form. Despite Bertolt's crimes, it is shown that his death still haunts Armin, as seen in the latter's nightmares. Due to acquiring Bertolt's memories, Armin has gained a deeper understanding of his predecessor's actions, and even compares his attack on Marley to Bertolt's attack on Shiganshina.
 * Marco Bott - Armin noted that they were friends, and did maintenance of their equipment together. This later allowed him to recognize Marco's stolen equipment when it was presented by Annie as her own.
 * Erwin Smith - Armin held the Commander of the Survey Corps in high esteem. Although he could not always guess his superior's inner thoughts, Armin regarded him as a highly smart person and a very capable commander who was not afraid of making sacrifices to reach his goals. When he heard that Erwin could have been saved instead of him by getting a Titan injection, Armin agrees that the injection should have been given to him, further highlighting how much respect and value Armin saw in Erwin.
 * Onyankopon - Ever since meeting after the arrival of the first survey ship to Paradis, Armin has been fascinated by Onyankopon. Having met a like-minded individual, they would frequently discuss issues such as how the people of the world came into being and expressed a fascination about them all being created by a similar God. When Onyankopon professed his innocence and that he did not agree with Yelena and Zeke's euthanasia plan, Armin recalled their numerous discussions and immediately believed him.

People killed

 * One member of the Anti-Personnel Control Squad
 * Bertolt Hoover (as a Pure Titan)
 * Marleyan naval fleet
 * Numerous Marleyan civilians

Failed attempts

 * Theo Magath

Trivia

 * Armin ranked tenth in the First Character Popularity Poll.
 * Armin ranked sixth in the Second Character Popularity Poll.
 * Armin ranked eighth in the Third Character Popularity Poll.
 * The name "Armin" may have multiple meanings, either from an old German word meaning "whole," or "Herman," meaning "soldier."
 * Hajime Isayama chose the name "Armin Arlert" since it sounds similar to the word "aluminum" and because starting both names with the same letter makes it easier to remember.
 * His birthday, November 3, is celebrated in Japan as Culture Day. This holiday promotes academics, culture, and the fine arts.
 * Armin's blood type is O.
 * Hajime Isayama has said that he does not see Armin and Eren being best friends forever.
 * This proved to be true after Eren joined the Yeagerists and severed all connections to his friends and the Military, including Armin and Mikasa.
 * In the side art for Volume 11, Armin, along with a few other characters, were depicted transforming into a Titan. His form had a large head that was almost the same size as his small body. This was also included in the second OVA.
 * Hajime Isayama joked in the November 2014 issue of Bessatsu Shōnen Magazine that the girl Mikasa got along with most was Armin. After much confusion, he later corrected himself and stated that Armin is in fact male.
 * Armin is the only member of the current Squad Levi to not be in the top 10 graduates of the 104th Trainee Corps.

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أرمين أرليرت Armin Arlert Armin Arlert Armin Arlelt Armin Arlert アルミン・アルレルト Armin Armin Arlelt pt-br:Armin Arlert Армин Арлерт 阿爾敏·亞魯雷特