Erwin Smith.

Erwin Smith (エルヴィン・スミス Eruvin Sumisu?) was the 13th commander (団長 Danchō?) of the Survey Corps. Discerning, intelligent, and widely respected, Erwin was an able commander. While he cared deeply for his men, he did not hesitate to sacrifice them for the good and prosperity of mankind, and his men proved more than willing to stake their lives at his order. During Erwin's career he developed the Long-Distance Enemy Scouting Formation, and due to uncertainty about his future, he later named Hange Zoë as his successor.

Erwin had a commanding presence, standing tall above most members of the Survey Corps, and had a quite muscular build with his blond hair kept neatly parted on the left side.

Erwin always wore a calm and collected expression on his face, with his icy blue eyes being one of his most striking features. His eyebrows were also quite noticeable, being very thick and bushy. Erwin typically dressed in the standard military uniform, donning the Survey Corps' signature green cape when on missions. He also wore a small, emerald bolo tie around his neck similar to the other military commanders, Nile Dok and Dot Pixis.

Erwin was a complex character, portrayed as serious, calculating, and always planning far in the future. While he trusted his men, he was the first to realize that there was a spy interfering with the Survey Corps, and was able to come up with a reasonable criteria to determine which of his soldiers to trust with vital information, and which to keep in the dark. An eloquent speaker, Erwin was able to sway many people, such as the military tribunal held to judge Eren and the trainees into choosing which recruitment branches to join.

Erwin was often seen as a very grim individual. He accepted all news, good or bad, mockery or praise, with the same stoic attitude. His ultimate goal was for humanity to once again rise up and become the dominant species over the Titans, a goal he was willing to sacrifice anything for, such as when ordering everyone to save Eren even after being caught in the jaws of a Titan, resulting in the loss of his right arm.[6]

He shared this unique stoic quality with men such as Garrison Commander Dot Pixis, team leader Ian Dietrich, and Commander-in-Chief Darius Zackly. As Armin Arlert put it, Erwin, like the aforementioned three men, had the ability to send his men to die if it would further the cause of humanity. He and they would sacrifice their own humanity in order to bring change to a world where those who cannot sacrifice things important to them will not change anything. Since he was able to make such commitments, he was a master strategist, shown multiple times through actions like capturing the Female Titan and leading a group of Titans to distract the Armored Titan so the military could save Eren.

However, behind his front of assurance and single-minded determination, Erwin still held his own personal ideals and questioned his own motivations. Following the rebellion, he admitted he understood his audacious actions and questioned constantly if what he was doing was the right thing.

Darius Zackly and Dot Pixis were also privy to this, with Zackly hypothesizing that Erwin did not truly care about humanity's best interests,[8] and Pixis openly accusing Erwin of caring more about his own life than the survival of humanity as a whole.[9]

These views of Erwin proved, in the long run, to be true. During his final expedition in Shiganshina, when faced with the prospect of sacrificing his own life in order to defeat the Beast Titan, Erwin proved reluctant to act, even considering abandoning his comrades for a slim chance of reaching the basement. Only after being coerced by Levi did he reveal his strategy. He cared more about discovering the secrets hidden in Eren's basement and finally proving his father's theories correct - possibly as a means to alleviate his guilt for the part he played in his death - than he did about retaking the lost territory of Wall Maria. His dream of understanding the world was so strong that he confessed to Levi that he considered it more important than the victory of humanity.[10]

This selfishness should not, however, be mistaken for heartlessness. He felt great remorse for sacrificing countless others for the sake of his ambitions, admitting to Levi that he felt their fallen comrades watching him, waiting to see what he would do with the lives that they dedicated to him.[11] This had rendered him suicidal; only his obsession with learning the truth about the world pushed him forward. Furthermore, despite his desire to understand the truth of the world being stronger than humanity's victory, Erwin made the selfless decision to go charging in the front lines alongside his soldiers and sacrifice the chance of knowing what was in the basement, effectively abandoning his dream.

As a child, Erwin was a curious and insightful individual who did not accept facts at face value. He asked why humanity had no memory of what happened before they lived within the Walls, because even if they had lost all their records, the first generation should have been able to teach their children. His father shared a theory with him that the king had altered humanity's memories when they first entered the Walls so he could control them better. Too innocent to realize why his father would not discuss this in the classroom, Erwin shared it with the other kids in town, which resulted in his father's "accidental" death, arranged by the Military Police Brigade's First Interior Squad.[13][14]

Erwin later enlisted in the Training Corps where he became friends with Nile Dok, with whom he shared his theory about the Royal Government hiding the truth about the world.[15] The two of them planned to enter the Survey Corps together, but they fell in love with the same woman at their favorite bar. Erwin gave up on a relationship with Marie so he could continue pursuing the truth and Nile changed his plans to marry her. After graduating, Erwin joined the Survey Corps, where he stopped sharing his theory with others. He realized that everyone else was fighting for the sake of humanity, whereas he was only fighting for himself. Nonetheless, he thrived as a soldier and eventually was given subordinates under his command.[17]

While a Squad Leader, Erwin devised the Long-Distance Enemy Scouting Formation as a way to minimize casualties while on expeditions. His proposal was rejected by then Commander Keith Shadis, who told him to try it when he became commander himself. Although his proposal had been rejected, Erwin began implementing his strategies in his own squad, and over time other soldiers and the populace began to notice that his squad would take no casualties, whereas Shadis would often be the only survivor of his charges.

Long ago, humans were just food for the titans. Until humans built three giant walls around their country. Wall Rose is the second outermost Wall following Wall Maria. It was breached by the Colossus Titan 5 years after the fall of Wall Maria, but the breach was later sealed by military efforts of the three branches and help from the Attack Titan. Wall Sina is the innermost Wall protecting the kingdom where the king and other civilians reside. The cities of Wall Sina are protected by the Military Police serving under the king. The underground is poorer and more prone to criminal activity. Wall Maria is the outermost Wall of the human kingdom. Like the other Walls, Wall Maria is approximately 50 meters in height. Five years ago, it was breached, after a century of peace and prosperity, and was lost to the Titans. The human military against the Titans is divided into three divisions: the Survey Corps, which explores the areas outside the Walls; the Garrison, which patrols and maintains the Walls, preventing Titans from entering the Walls in case the gates are breached, primarily to delay and distract the Titans; and the Military Police, high-ranking soldiers who serve as personal guards for the King and maintain order within the Walls. The Survey Corps (調査兵団 Chōsa Heidan?) was the branch of the Paradisan military most actively involved in direct combat with and study of the Titans. Due to their constant expeditions, the Survey Corps' soldiers were the most proficient in the use of the 3D Maneuvering Gear and the Anti-Personnel Spatial Maneuvering Device. Despite little success from their activities, the members of the organization still symbolized the "hope of humanity", and their insignia was known as the "Wings of Freedom". The Survey Corps' goal was to someday change the world and take back what was taken from humanity.

Garrison (駐屯兵団 Chūton Heidan?) is the most numerous, but also the least qualified (except for elite units) branch of the military. Due to the high mortality rate of the Survey Corps and the high competition for recruitment into the Military Police, people most often prefer it. The main task is to protect the Walls during an attack by the Giants and the subsequent evacuation of the civilian population. Secondary: organizing order, patrolling, repairing defensive structures. In the battle for Trost, the Garrison fighters not only defend the walls, but also independently clear out the captured areas. It was they, along with the cadets, who participated in the defense of Trost, only then the Survey Corps cleared out the city. The Military Police (憲兵団 Kenpeidan?) is the most prestigious branch of the military. This is because their job allows them to live within the inner walls, in safety. The Military Police have a lot of resources, and their power is greater than that of the Garrison and the Survey Corps. In reality, the Military Police have a complete lack of supervision and discipline, abuse of power can be seen everywhere, they have a bad relationship with the Garrison and almost hateful with the Survey Corps. Only the top ten cadets can get into this branch of the military, but judging by the conversation between Boris and Hitch, there are other, illegal ways to get into the police. Most titans are pretty stupid, but despite this, killing even one titan is quite problematic. Only one weak spot has been discovered in titans - the neck. If you cut even part of a titan's neck, it dies immediately.