Armin

Armin Arlert is one of the two deuteragonists (alongside Mikasa Ackerman) of the Attack on Titan anime/manga series. He is a refugee from Shiganshina and Eren Yeager and Mikasa Ackerman's best friend from childhood. Although he is physically weak and hates having to rely of Eren and Mikasa, Armin's strategic abilities and intelligence more than makes up for his physical foibles and have saved Eren and Mikasa multiple times. He is instrumental in discovering the identities of the Titan infiltrators, and becomes one of the Survey Corps' most vital members. In fact, Armin's brilliance is not only recognized by his comrades and superiors alike, his strategic capabilities can reach and appeal directly to Erwin Smith, the supreme leader of Survey Corps, bypassing typical military chain of command.