Armin
Arlelt

Armin was the boy who got beaten by bullies rather than run, and who owned a forbidden book about the outside world. The sea in that book, a lake of salt too big for any merchant to empty, was his and Eren's shared dream long before either of them understood what the walls were really for. He judged himself the weak one of the three friends his whole life, and kept being the reason the other two survived.

His record as a tactician built up quietly. He planned the retake of the Trost supply depot while everyone else despaired. He worked out that the Female Titan was a person, then that the person was Annie, and set the trap that caught her. At Shiganshina he deduced that Reiner was hiding inside the wall itself, and then burned nearly to death clinging to the Colossal Titan's teeth so Eren could set up the decoy that beat Bertholdt. He was given the single Titan serum on that rooftop, over the dying Erwin, because Eren and Mikasa drew blades for him. He ate Bertholdt, inherited the Colossal Titan, and never stopped carrying the question of whether the wrong man was saved.

He used the stolen Colossal exactly twice at scale, and the port of Liberio taught him what Bertholdt must have seen. Through the years Annie spent sealed in crystal he kept visiting and talking to her, and she heard all of it. Hange named him commander of the Scout Regiment before walking off to die at Odiha. On the boat to that battle Eren showed him everything and then sealed the memory, so Armin fought his best friend without knowing they had already said goodbye. When it was over he introduced himself to Marley's commander as the man who killed Eren Jaeger, and three years later he sailed back to Paradis as an ambassador, still arguing for talking before fighting.