Eren's best friend, despite being physically weak, possesses emotional strength. Although lacking combat skills, Armin excels in theoretical courses and can plan effectively under pressure. However, he constantly thinks of his perceived weakness and does not recognize the contributions he makes to Eren and Mikasa. He feels incompetent and hates himself for relying on them.
19 (after time skip)
After the battle of Shiganshina District, he took the power of the Titans from Bertolt Hoover and came in possession of the Colossus Titan.