At one point, I was doing a mental comparison of Jane Eyre's use of "master" and Jeannie's from I Dream of Jeannie. While it's sort of a slave term, neither one obeys all the commands of her "master." Jeannie uses the word ironically and as a word of endearment, sometimes almost possession. Jane uses it also as an endearment term and as a way of deriving comfort from someone stronger than herself.
But I completely overlooked another "master," most surprisingly because this time it is also accompanied by another Jane. You'll recall that the Jane of Twilight calls Aro "master" quite frequently. I think many of us are amused by Jane and Aro's relationship: it's somewhere between father/daughter and master/slave. Part of the reason for this, I'm sure, is because Jane is so young: although she has been around for many, many years she is still a child. So I think Aro has taken advantage of her youngness to gain her loyalty. Unlike Jane Eyre and Jeannie, Jane uses "master" in its fullest sense: she does not disobey Aro's orders according to her own will. His will is her will.
Be the differences as they are, I still think it is no coincidence that the character so frequently using the word "master" is named Jane.