Mary Robinette Kowal’s debut novel, the Jane Austen fantasy pastiche Shades of Milk & Honey, was published to critical acclaim (not to mention award nominations) in 2010, and since then, she has followed husband-and-wife “glamourists” Jane and Vincent through three subsequent, ever-more-daring adventures. Next month, Tor Books will publish the fifth and final volume of the series, and we gave Mary a chance to share her thoughts on parting with characters and a world that have been with her for the better part of a decade.

People keep asking me why I’m closing the Glamourist Histories series with Of Noble Family. It’s true. I could keep writing in my “Jane Austen with magic” universe forever. Even if the novels weren’t about Jane [née Ellsworth] and Vincent, there’s the rest of the world to explore.

My feeling was that, as a reader, I start to fatigue after about five books. I thought about why that was, and realized that in each subsequent book, the author has to continue to raise the stakes. After a certain point, it either becomes repetitive, or too brutal to bear. I figured, after the things that Jane and Vincent have endured, they would be walking bundles of PTSD by the sixth book and would spend the entire novel huddled in the closet. What I didn’t expect, upon finishing the last book, was that I would mourn Jane and Vincent.

While I write short fiction and have other novels in the pipeline, these characters have been with me since 2006, when I wrote a short story which would become the first chapter of Shades of Milk and Honey. It has become my habit to idly think about adventures for them. Many of those wind up in the books.

Of Noble Family, in fact, came about because I was reading Jane Austen’s Mansfield Park and wondered what it would be like if Jane and Vincent went to Antigua the way Sir Thomas does.

In Mansfield Park, Sir Thomas goes to his estate in Antigua and is gone for a year, with word coming back from him only sporadically. To a modern reader, it looks as though Jane Austen doesn’t really touch on it at all, but the issue of slavery was huge in England in the early 1800s. Most of the citizens wanted to see it abolished, and only a small group of people with estates in the West Indies managed to lobby to keep it in effect. It probably would have been outlawed in the late 1780s or 1790s if not for parliamentary mismanagement. So for Jane Austen’s audience, she could make subtle references to it and have them be very pointed indeed.

For a modern reader, I have to help them understand how things were in 1818. And things were grim: One of the outline drafts would have seen Of Noble Family end with blood and then more blood. That wasn’t the right way to end the Glamourist Histories. So, my challenge was to write something that accurately reflects the horrors of a slave plantation, while at the same time delivering the reading experience that my readers have signed up for.

That meant a focus on family, and very specifically on Jane and Vincent’s marriage. The thing that I have loved most about writing these books, and what I will miss the most, is that I have in my leads a happily married couple in a fully committed relationship. They are so goofily in love with each other, even when things aren’t perfect. I don’t get to read enough stories about married couples.

I’ll miss writing them.

Pre-order Of Noble Family, available April 28.