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The name used is an alias, nickname or surname found in an official source, but the actual in-universe name of this person is unknown in this continuity.
Erwin's father was a tall, lean old man with short light-colored hair, circular glasses, and an unkempt beard and mustache. His hair was kept parted on the left side and his face showed distinct cheekbones and wrinkles. Erwin's father wore a white shirt with the sleeves rolled up and dark gray pants when teaching his class.
Erwin's father appeared to be highly intelligent, considering how he theorized about the Walls. He also cared deeply for his son's future, so much that he did not reveal his "dangerous" theory in his history class for his sake and the students', but later told Erwin.
In Erwin's youth, Erwin's father was a teacher in their hometown. One day he was teaching history when a young, bright-eyed Erwin Smith asked him a question. He vaguely avoided it, ending class soon after. When they made their way home, he sat Erwin down and gave him an honest answer to his question based on what he believed. He mentioned that the history books, distributed by the government, were full of mysteries and contradictions. He believed that it was near impossible for humanity not to have passed down an oral history. Instead, the only way to ensure that humanity forgot about the history before the Walls would be to alter their memory in some way.
Due to Erwin's naivety, the Military Police caught wind of Erwin's father's theory. He was then secretly detained and tortured for what he knew. His body was then dumped in a far-off town, made to look like an accident.
When Nile Dok is speaking to the other Military leaders about his past with Erwin, he reveals that the question he asked his father that led to his subsequent death and Erwin's dreams of knowledge about the outside world was "How did they find out that there aren't any humans outside the Walls?."
- Erwin Smith - Erwin's father trusted his son so much that he revealed his dangerous theory about the Walls to him. But Erwin ended up telling other children about this theory and the Military Police caught wind of it which led to his father's death.
- Erwin's father is one of five people believed to be tortured and killed by Djel Sannes and the Military Police Brigade.
- He shares a birthday with Marlowe Freudenberg and Peaure.