Reiner Braun, a brawny first-year student at Attack Junior High School, sports short blond hair and a muscular build, typically clad in the standard uniform. Blending stubborn determination with unwavering loyalty, he actively mentors shy best friend Bertholdt Hoover, bolstering his confidence and social skills. His persistent romantic pursuit of Christa Lenz manifests in festival invitations and bold flattery, though Ymir’s vigilant interference—physically and verbally blocking his advances—thwarts every attempt.

A natural leader in school events, Reiner spearheads dodgeball teams, sports day relays, and the prank-centric Test of Courage, where he and Bertholdt expose a fabricated ghost haunting. He engineers tactical plans to aid Bertholdt’s courtship of Annie Leonhart, but Mikasa’s rivalry with Annie and chaotic misunderstandings derail their efforts, such as during the summer festival’s commotion.

His campaign for student council president implodes after proposing mandatory training camps and swimming meets to “foster peer bonding,” illustrated by a controversial slideshow of female students in swimsuits. The backlash, particularly Christa’s horrified reaction, forces him to abandon the podium mid-speech.

Socially relentless, Reiner vows to marry Christa after seeing her in a maid café outfit, undeterred by Ymir spiking his curry with hot sauce. He later backs Eren Yeager’s rogue mission to reclaim stolen lunchtime cheeseburgers, defying teachers to support his peer.

Bertholdt remains his steadfast confidant, with Reiner prioritizing his friend’s growth and romantic goals. Ymir’s antagonism escalates into physical comedy to shield Christa, who responds to his affections with detached courtesy. His abrupt transfer to Marley Academy after freshman year concludes his junior high arc.

Design-wise, Reiner’s features blend David Beckham’s sharp eyebrows and eyes with traits borrowed from the original creator’s acquaintance. His surname, meaning “brown” in German, reinforces his earthy, grounded persona.