Armin Arlert is a character from the manga and anime series Attack on Titan. He is a graduate of the 104th Training Corps and a childhood friend of Eren Yeager and Mikasa Ackerman. He is known for his high intelligence and strategic genius, which makes him an invaluable asset, especially when paired with Hange Zoë. After the battle of Shiganshina District, he took the power of the Titans from Bertolt Hoover and became the Colossal Titan.