From Nathaniel’s childhood up until his last moments alive, the Sandman rules over his actions and thoughts, and slowly consumes him. Nathaniel’s letters demonstrate intelligence, attention to detail, and kindness, as well as some condescension toward Clara. His clear writing about odd circumstances in his life creates an ambiguity about what is real and what is imagined in the letters. Given the anxiety and mental stress described, Nathaniel cannot be considered a reliable narrator. However, instead of making Nathaniel completely unreliable, Hoffmann paints a portrait of a young man who can be reasonable at times.

As a young boy, Nathaniel finds himself fascinated and horrified by the rather gruesome tale of the Sandman, particularly the part about the Sandman causing children’s eyes to pop out of their heads, and this fear grows over time. Hoffmann never truly reveals whether Coppelius’s attempt to pull out Nathaniel’s eyes actually happened or if it was a fever dream of Nathaniel’s. But whatever happened causes Nathaniel to permanently merge Coppelius and the Sandman together in his mind.

Nathaniel’s growing obsession with the Sandman story seems to begin when he is about nine years old, around the age society expects children’s interests to move beyond fairy tales and bedtime stories and into real-world interests. However, even as an adult, Nathaniel’s childhood fears and fascinations are easily triggered by a door-to-door salesman, suggesting Nathaniel’s childhood trauma causes him to remain very much a child in some ways. His attraction to Olympia, an automaton, reflects this delay in maturity as Nathaniel essentially chooses a doll over a real woman.