Reiner Braun is a character in the popular anime Attack on Titan. He hails from the Eldia tribe and serves as a warrior for the Marley. Alongside three other companions – Marcel, Annie, and Bertholdt – Reiner possesses the power of the titan. The group is sent on a mission to the paradise island to accomplish a task, but before they could complete the mission, Marcel is eaten by a titan named Ymir. Annie, Bertholdt, and Reiner transform into titans and break through the wall of Maria. They later blend in with the crowd, disguised as members of the military. They perform their duties well for five years before their true identities are eventually uncovered.
During their five years working together, they spent time with Eren and the others, sharing stories and sympathizing with each other. They show no signs of suspicion about their backgrounds. One day, Annie’s mission is to capture Eren in the form of a Female Titan. However, she escapes after losing to Eren and the scouts. Later, Hange Zoe is shocked when one of her research subjects is killed, leading to the suspicion of Annie.
When Annie is caught protecting herself in a crystal, Reiner and Bertholdt are also suspected due to their similar origin. Their suspicions are proved correct when Bertholdt transforms into the colossal titan while Reiner becomes the armored titan. During their conversation with Eren, both of them express doubts and sadness about betraying their friends, especially Bertholdt. In the Shiganshina district, Berthold is killed, and his power is taken by Armin. Meanwhile, Zeke is defeated by Levi, and Eren defeats Reiner, and both are saved by the transport titan.
Returning to Marley, Reiner experiences a personality disorder, as seen in his behavior during dinner with Gabi and her family. He appears more gloomy and doesn’t seem to have the energy to continue living. Even when Eren meets him during the festival in Liberio, Reiner looks extremely disheveled and gives up on life. Though Reiner has managed to return to Marley safely, his mental state is affected. He was once enthusiastic about accomplishing his mission, believing it was for the betterment of humanity. However, he eventually realized, too late, that he was fed a false doctrine about the Eldia tribe being demons that needed to be eradicated. In reality, they were just regular people. The tragic story of Reiner, Zeke, Bertholdt, Gabi, and the Eldia tribe fighting for Marley only ended up in failure as they betrayed their own humanity mission.
