The Training Corps is the mandatory three-year military training program that all Paradis citizens must complete upon turning twelve years old. It serves as the foundational military education system, transforming civilian adolescents into capable soldiers ready for assignment to one of the three main branches. The curriculum covers ODM gear operation, Titan anatomy and weak points, hand-to-hand combat, survival skills, military discipline, and tactical theory. The most famous cohort is the 104th Trainees Squad, stationed at the Southern Training Corps camp under the supervision of Chief Instructor Keith Shadis, which produced an extraordinary number of key figures who would shape humanity's future.
The Training Corps functions as the military's recruitment and basic training pipeline, ensuring every adult citizen has fundamental combat skills and knowledge of Titan threats. Trainees are evaluated over three years, concluding with graduation exams that determine their branch assignment eligibility. The top ten graduates earn the privilege of joining the Military Police within Wall Sina, while the remaining graduates are assigned to the Garrison Regiment or may choose to volunteer for the Survey Corps. Beyond combat training, the Corps also instills military hierarchy, teamwork under pressure, and the psychological preparation needed to face Titans. The 104th Training Corps class was unique in producing graduates who fundamentally changed the course of human history through their actions and discoveries.
Keith Shadis was the Chief Instructor of the Southern Training Corps, a former Survey Corps commander who retired after a failed expedition that haunted him for years. He trained the entire 104th class with harsh discipline and genuine care, recognizing Eren's burning determination from the very first day. The 104th Trainees Squad produced Eren Yeager, the future Founding Titan who would initiate the Rumbling; Mikasa Ackerman, the prodigy who graduated at the top of the class; Armin Arlert, whose strategic brilliance surpassed all expectations; and Reiner Braun, Bertholdt Hoover, and Annie Leonhart, the Warriors infiltrating Paradis as enemy agents.