Authors have to make up names for characters mainly in order for their readers to be able to tell the characters apart. However, when there is only one character in a story the author may not feel obliged to give him or her a name. What purpose would be served by giving the protagonist in "To Build a Fire" a name. The author Jack London can get by comfortably just by calling his character "he" or "him" or "the man." For variety London sometimes calls him the chechaquo. The dog isn't given a name either, but in some of London's stories involving dogs he has to invent names because there are several dogs involved, as in The Call of the Wild. It is possible to read too much into the fact that a character in a story doesn't have a name. The protagonist in Jack London's "To Build a Fire" is described in considerable detail both in appearance and in his thoughts and feelings. He is not an important person, but in the story he is all-important to the reader just because he is a fellow human being. Some people attach a lot of importance to the fact that in his novella Of Mice and Men, John Steinbeck doesn't give Curley's wife a name. But she is the only female character in the book and doesn't really need a name. A name would only cause confusion. If Steinbeck named her, let us say, Margaret, then some readers might get the idea that there were two female characters in the story, one called Margaret and another called Curley's wife. Names are usually invented to enable readers to tell characters apart. Some writers are good at inventing names, while other writers are not.
Stephen Crane once wrote a poem entitled "A Man Said to the Universe." The poem is as follows:
A man said to the universe:“Sir, I exist!”“However,” replied the universe,“The fact has not created in meA sense of obligation.”
Then it turned and trotted up the trail in the direction of the camp it knew, where were the other food-providers and fire-providers.
And Spring herself, when she woke at dawn
Would scarcely know that we were gone.