Leaving the walls
Eren and Armin imagine the outside world long before they can reach it. When Shiganshina falls, survival takes the place of ordinary childhood. Joining the Survey Corps gives them a route toward answers, alongside Mikasa and under officers who know how rarely an expedition brings everyone home.
The same uniform, different responsibilities
The short jackets, harnesses and Wings of Freedom connect soldiers whose abilities are far from equal. Levi must lead people he cannot always save. Mikasa's scarf preserves a life before military service. Armin learns to trust the ideas his friends depend on, while Eren becomes a power the Corps can neither ignore nor fully control.
What the outside world changes
The basement and the journey to the sea overturn the history they were taught. Later uniforms and equipment belong to a conflict involving human enemies as well as Titans. Eren's actions eventually divide the companions who shared the earlier dream. Their changed appearances make more sense within that break than as a simple progression toward greater strength.
