Armin Arlert is a character created by Hajime Isayama.
- "While lacking in physical strength, he's demonstrated an extraordinary aptitude for his studies."
- — Keith Shadis (Episode 4)
- Eren Jaeger - He and Eren are close friends. Often, Eren and Mikasa save Armin from bullies. Armin wants to return the favor to them by fighting alongside them in the Scouting Legion to prove he is strong. He and Eren share interests in the outside world when Armin shares about the sea, islands, and other environments from books.
- Mikasa Ackerman - They are close friends. Armin cares for Mikasa as much as he cares for Eren. When Armin thought Eren was dead, he is devastated and struggled to tell Mikasa about it. He is touched by Mikasa, who wouldn't leave him behind.