Answer:
The narrator plays a central role in "To Build a Fire."
Early in  the story, he points out the main character's lack of imagination. Â
This is very important, as this lack of imagination will do the man  in.
The man makes many crucial mistakes.
A lack of  imagination contributes to these mistakes and costs the man his life.
Explanation:
The last sentence* is no longer needed because the narrator's identity was revealed earlier when this passive sentence** was changed to active voice.
*  The narrator suggests this might be the case at the very  beginning of this harrowing tale.
** Early in  the story, the main character's lack of imagination is pointed out.