|The Armored Titan specializes in hardening. If it charges in at full speed, the gates of any wall will crumble.|
|— A Marleyan analysis of the Armored Titan|
The Armored Titan (鎧の巨人 Yoroi no Kyojin?) is one of the Nine Titans that possesses armored plates of skin across its body. It is currently in the possession of Reiner Braun, although Gabi Braun is a candidate considered to inherit the power from him. It is an elusive threat to humanity within the Walls, first appearing five years ago during the fall of Wall Maria.
The defining feature of the Armored Titan is the all-encompassing layer of plated, armor-like segments of hardened skin protecting the Titan body. This armor is capable of protecting the Titan from significant amounts of damage, even a direct hit from a cannon or the ultrahard steel blades of ODM gear. However, the armor has some limitations and is incapable of protecting the user from high-power weaponry such as the Mid-East Allied Forces' anti-Titan artillery. Along with providing formidable physical protection, the armor can also be used offensively, dealing devastating damage upon impact, and is even strong enough to ram through the gates of the Walls.
The primary disadvantage of the Armored Titan's skin is the decreased speed of the Titan form. Whether due to increased weight or restrained movement, the Armored Titan is incapable of moving at high speeds when completely armored. This can be alleviated if the user chooses to shed segments of the armor to increase movement capability and speed, such as the armor behind the knees.
Similar to the Female Titan, the Armored Titan is capable of utilizing crystal-like hardening around its body to at least some extent. The Armored Titan can also use this ability to create claws on its hands and feet which can be used to scale the Wall of Shiganshina District with ease.
The Armored Titan, like all the Nine Titans, was brought into the world after the death of Ymir Fritz. In the 1,700 years following her death, the Armored Titan was held in the possession of one or several of the warring Eldian houses subservient to the Founding Titan. After these seventeen centuries when Karl Fritz, the 145th king of the Fritz family, abandoned the conflicts of Eldia and relocated to Paradis Island, the Armored Titan was taken by the nation of Marley during the Great Titan War.
In the year 843, Reiner Braun was chosen to inherit the power of the Armored Titan. He would later make use of his Titan form in a war between Marley and an enemy nation, using his Armored Titan to take the brunt of enemy artillery fire.
The Armored Titan first appears in the year 845, shortly after the Colossal Titan first breaches the south gate of Wall Maria, participating in the attack on Shiganshina district. During the chaos of the initial breach, Reiner's Armored Titan enters the city and makes its way across the streets to the north gate. Once there, it charges towards the gate and smashes through it, allowing Titans to invade Wall Maria. Reiner joined his fellow surviving Warriors in entering the walled territory during the chaos, and he would not use the Armored Titan for another five years.
When Reiner, in a moment of exhaustion and desperation, reveals himself to be the Armored Titan and exposes Bertholdt as the Colossal Titan, the two transform into their Titan forms and battle against the Scout Regiment. Reiner's Armored Titan captures Eren Jaeger, descending from Wall Rose with the recruit in his grip until Eren transforms into his own Titan, ready to battle.
The Armored Titan initially overpowers Eren's Titan until it makes use of a technique that was taught to him by Annie Leonhart while they were cadets. This allows him close enough to grapple with the Armored Titan and break off his right arm. Eren retreats to the Wall to avoid capture, but the Armored Titan charges after it. Hange Zoë realizes that the Armored Titan cannot be completely armored if it is able to move that quickly and must have weak points like in the joints of a suit of armor. While the two Titans grapple, Mikasa Ackermann cuts through the back of the Armored Titan's knee, weakening its ability to fight. Eren's hold begins to break through the Armored Titan's plating, threatening to tear off its head. With defeat imminent, the Armored Titan roars, signaling Bertholdt's Colossal Titan, which falls on the two Titans. This allows Reiner the opportunity to bite Eren out of his Titan and escape while the Scout Regiment is unable to stop them.
Reiner and Bertholdt take a break in a Forest of Giant Trees, but when the Scouts pursue them sooner than expected they flee using their omni-directional mobility gear because Reiner says his Armored Titan is too slow. He refrains from using it until they get to the edge of the forest, and then he transforms. Bertholdt, carrying a captured Eren, and Ymir in her Titan form, carrying Historia, ride on his shoulders.
The soldiers chase after them on horseback and Reiner is not fast enough to outrun them. When they begin attacking, Bertholdt calls for him to protect them and Reiner closes the Armored Titan's hands over Bertholdt and Eren, so they cannot be taken away. However, he does not count on Commander Erwin Smith leading a horde of Titans into him.
Though he tries to charge through, the Armored Titan is overwhelmed and forced to a standstill due to the sheer numbers of Titans that grab on to him. Realizing that he will gradually be worn down, Reiner lifts his hands to bash away the Titans, though it exposes Bertholdt and Eren and ultimately allows Eren to be rescued.
Unable to immediately chase after the fleeing soldiers, Reiner begins throwing Titans at the Scouts in order to stop them, apparently not caring if Eren is eaten. Gradually, he removes enough that the Armored Titan can begin moving again. In the middle of the fighting, Eren strikes one of the Titans and activates the Founding Titan that Reiner was searching for. Reiner charges at him, but Eren's outburst causes the Titans to focus their attacks on him and Bertholdt.
The Armored Titan survives the battle and Reiner retreats to Wall Maria along with Bertholdt and Ymir.
Some time later, Reiner's Armored Titan battles Zeke's Beast Titan over their next course of action. The Armored Titan is soundly defeated in the brawl, and Zeke states that they will wait in Shiganshina for the arrival of the Scout Regiment rather than attempting to rescue Annie Leonhart.
Three months after the Struggle for Trost, the Scout Regiment arrives in Shiganshina and seal the southern breach using a new hardening ability acquired by Eren's Titan. Suspecting that the Warriors may be nearby, Armin Arlelt proposes a search of the Wall and Reiner is found hiding within. As he is brutally attacked by Captain Levi, Reiner still manages to transform into the Armored Titan after using a last-resort ability to transfer his brain functions to the entirety of his body.
As the battle of Shiganshina District begins, Reiner hardens his fingers to climb Wall Maria in order to attack the Scouts' horses. However, Eren's Titan appears in the city and Reiner is left with a choice, and he chooses to confront Eren. The Armored Titan fights against Eren for a second time.
Eren's new ability to harden his Titan's skin successfully deals heavy damage to the Armored Titan, but the greatest damage is dealt from the Thunder Spears, a new explosive weapon developed by the Corps of Engineers in recent months. The explosives tear through the armor of Reiner's nape and destroy his brain, though his consciousness transfer once again keeps him alive. The Armored Titan calls for plan B, the Colossal Titan, and shortly thereafter Bertholdt arrives at Reiner's side, telling him to lie down on his back for the time being.
While Bertholdt confronts the Scouts, Reiner follows Bertholdt's advice and the Armored Titan lies down on its back, protecting Reiner from further harm and allowing for him to regenerate his body. A short while later, Reiner fully heals his brain and the Armored Titan returns to the fight, but with no memory of any events that had occurred since earlier that morning. Squad Levi attacks Reiner with the Thunder Spears again, incapacitating it and successfully bursting Reiner from the nape of the Armored Titan.
Four years later, Reiner is present at the battle of Fort Slava at the climax of the Marley Mid-East War, waiting on standby in an airship due to the presence of anti-Titan artillery on the ground below. Once the ground infantry succeed in destroying the armored train carrying the artillery around the fortress, Reiner eventually joins the combat as the Armored Titan after a Titan airstrike sent down with the power of Zeke's Beast Titan. Alongside Porco Galliard's Jaw Titan, the Armored Titan decimates the anti-Titan artillery set up on the walls of the fortress. When the coast is clear, Reiner's Titan signals for the Beast Titan to join the battle, where it throws spare artillery at the Mid-East Allied Forces' navy stationed in the bay nearby. However, when the ships begin to open fire on the Beast Titan, Reiner uses his Armored Titan as a shield for Zeke, receiving devastating damage in the process.
- In a blog post, Isayama revealed that Reiner's Titan image (the Armored Titan) was actually based on Brock Lesnar, an American professional wrestler, and former Mixed Martial Artist.