Reiner Braun.

Reiner Braun (ライナー・ブラウン Rainā Buraun?) is the Vice Captain (副長 Fukuchō?, also translated as "Deputy Chief" or "Vice Commander") of the Warrior Unit. He is the illegitimate son of an Eldian and a Marleyan and grew up in Liberio's internment zone. Eventually, he was selected as a child to become one of Marley's Warriors. At the age of ten, he inherited the power of the Armored Titan. In the year 845, he infiltrated Paradis Island alongside Bertolt Hoover, Annie Leonhart, and Marcel Galliard as part of an operation to reclaim the Founding Titan. He joined the Survey Corps after graduating 2nd in the 104th Training Corps.

In human form, Reiner has short blond hair, hazel eyes, and a defined facial structure. His large height, broad shoulders, and serious expression give him an intimidating presence.

In the year 854, Reiner has slightly longer hair, possesses a short goatee and has lost weight making his cheekbones appear more defined. He has also grown taller.

Reiner's Armored Titan form was 15 meters tall and had white plates of hardened skin covering the entirety of its body, except for muscles in its cheeks that become exposed when it opened its lipless jaw, as well as the muscle tissue behind its knees, elbows, and feet. Its eyes were covered by white, organic lenses, and it had short, blond hair. While fighting Eren, it has been noted that it had high agility and was capable of moving at a fast momentum, despite its seemingly-heavy weight and being low on stamina. His Titan was also able to harden its hands and feet which create sharp claws that could be used to climb certain structures, such as the Walls.

As a child, Reiner was rather quiet and meek yet at the same time very loyal and driven. He believed that if he became a Warrior then his Marleyan father would come back[16][17] and deluded himself into thinking he would still cheer him on as he fought the Eldians, even after he rejected him.[18] Because of his motivation, Reiner was very desperate to become a Warrior, even going as far as to accuse Galliard of being an Eldian spy when he belittled him. However, after he was chosen to inherit the Armored Titan, Reiner gained a newfound self-confidence, though it was quickly shattered when Marcel revealed that he was not chosen for his abilities.[19] Due to Marley's propaganda and his mother's influence, he believed the Eldians of Paradis Island to be "devils" and that he would become a hero by exterminating them.[20] He was also very gullible, never doubting the words of his mother and superiors. Following Marcel's death, Reiner began incorporating elements from his personality into his own. He became more decisive and assertive, even willing to threaten Annie and Bertolt to ensure they followed his orders, yet also deeply caring and genuinely desiring to protect them. He also accepted that his belief that his father would return if he were to become a Warrior and defeat the Eldians was just a fantasy. In addition to this, Reiner started to develop a negative perception towards himself, believing he was supposed to have failed in becoming a Warrior and that he should have been the one to die instead of Marcel. By the time he joined the 104th Training Corps, Reiner had completely incorporated Marcel's personality into his own. He built up a reputation of being a passionate and honest person with a strong sense of duty who takes his role as a soldier very seriously and encourages others to do the same. However, he was also noted to have a kind heart and a tendency to always think of others before himself, taking on extra burdens for the sake of his comrades.

Reiner comes from the Liberio internment zone in Marley, which he refers to as his hometown. He was born to an Eldian mother, Karina Braun and a Marleyan father. Growing up, he was not allowed to see his father, as relations between Marleyans and Eldians were strictly forbidden.[32] As a child, it was decided between him and his mother that he would become a Warrior candidate and potentially inherit one of the Nine Titans so that Reiner and his mother could become honorary Marleyans and reunite with Reiner's father.[33]

As a Warrior candidate, Reiner was very weak, his only skill being his strong loyalty to Marley.[34] One day, he learned from another Warrior candidate, Zeke, that in a few years, the operation to reclaim the Founding Titan would begin, and six new Warrior candidates would be chosen to inherit the power of the Titans.[35] He was mocked by Porco Galliard, a prime candidate to inherit the Armored Titan, for this, claiming that he would have to wait thirteen more years to inherit the Armored Titan. This led to a fight that ended when Marcel pulled his brother back and the others left with Zeke.[36] It was during this that he trained with fellow Warrior candidates Annie Leonhart and Bertolt Hoover. Bertolt attempted to convince Reiner to give up his aspirations, as he would only live for thirteen more years. But Reiner believed that after those thirteen years, he would be a hero to the people of Marley and be the best son in the world.[37] Marcel Galliard ultimately influenced the army, leading to Reiner being selected to inherit the Armored Titan in place of his brother Porco.[38] Alongside the other Warriors, the six Titans crushed an entire nation, leading to them being regarded as a stronger group than their predecessors.

Upon traveling to the island, the Warriors parted ways with the army at the border and began traveling by horseback under the cover of night.[41] While resting, Reiner learned of Marcel being the reason he was chosen to inherit the Armored Titan. As the sun began to rise, Marcel pushed Reiner out of the way of a Titan emerging from the ground, leading to the Warriors fleeing while Marcel was eaten.[42] This event appeared to have left him traumatized, as he remembered it in moments of stress and expressed an almost suicidal desire to place himself into harms' way for the sake of others.[43]

After the loss of Marcel, Annie and Bertolt wanted to cancel the operation but Reiner opted against it as he claimed to know the consequences. This prompted Annie to attack him for his cowardice. After getting beaten up, Reiner tackled her and declared his resolve to become the leader as Bertolt agreed to continue the operation.[44] When they got within eyesight of Wall Maria, Annie and Reiner switched places as the Titan carrying the other Warriors, as she was exhausted and at her limit. Reiner dropped Bertolt off at the Wall and retreated to allow him the room to transform.

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.