Eren was usually seen wearing a green shirt and a brown jacket. He had a fairly long, yet rounded face, and sizable, expressive green eyes. His eyebrows were sparse and often furrowed, which made him seem troubled or annoyed. His hair was short and dark brown, with his bangs that fell naturally into a middle-parted curtain-type style. His complexion also seemed somewhat tan.
Eren was always bent on joining the Survey Corps, despite having seen them come back all wounded. He always wanted to see what was beyond the Walls and had a pure hatred for those who disagreed with him.
Eren is mentioned by Annie Leonhart, whose mission consists in capturing him during the Expedition outside the Walls.