There are three significant character name changes in Davies' Fifth Business. The first is in the case of the main character, Dunstable Ramsay. To young Ramsay, Mrs. Dempster (his neighbor) becomes a saint after a dramatic change in her behavior following an unfortunate encounter with a snowball. While Ramsay is away fighting, he is very badly hurt in the war and is convinced that his saintly neighbor appears to him and saves him from death. During his recovery, a nurse speaks to him about St. Dunstan, who once had a run-in with the Devil. This influences Ramsay to change his name to Dunstan.

Percy Boyd Staunton, who was responsible for throwing the snowball, is the second character to have his name changed. He renames himself Boy Staunton after renewing his acquaintance with Ramsay many years later. A saintly, religious influence is evident in their name changes, as both men thus consider themselves "twice born."

Paul Dempster, the son of Mary Dempster, leaves home and eventually becomes a famous magician. His stage name is Magnus Eisengrim—another name change.

Ramsay, Percy, and Paul all get name changes to illustrate new phases in their lives and new personas. Ramsay and Percy both believe the name changes make them twice-born and somehow mythical. The new names give them a way to leave negative aspects of their pasts behind.

Ramsay and Percy both change their names partially stemming from trauma they suffer in the military. For Percy, it's directly tied to his name; people mock him for the name Percy. He uses his middle name without the -d and his last name to become Boy Staunton and, as Boy Staunton, has a happier and more successful life for a time. Ramsay, on the other hand, is catastrophically injured. When his nurse decides he should call himself Dunstan, he uses the name to live the new, second part of his life while removing himself from the trauma that came before.

Paul's case is a bit different. He wants to be a magician and knows that Paul isn't a good stage name. He christens himself Magnus Eisengrim, which seems much more magician-like. This lets him lead the type of life he desires.

Three characters in Robertson Davies' Fifth Business undergo name changes: Boy (Percy Boyd Staunton), Magnus Eisengrim (Paul Dempster), and Ramsay himself (Dunstable Ramsay)all undergo major changes in their lives. These changes represent internal changes in each of the characters, and the name change illuminates the internal change in an external way. For each of the characters, a new life is begun. In order for this new life to be whole, the men need new identities as well.

For example, Ramsay's name is changed by a nurse, Diana. It is her job to take care of him after he has had a massive leg injury (due to the war). After being refused by Ramsay, Diana changes his name to Dunstan. It is also important given he has been declared deceased.

Boy Staunton needs a new start after a bad one in the Army. The name Percy only brings him painful memories. In order to begin again, Boy drops the name Boyd.

Magnus Eisengrim began life as Paul Dempster. In order to fulfill his desire to be a magician, and given that Paul is not really the type of name a magician would use, Paul changes his name to Magnus.