First of all, tell me a little about your series and introduce us to the sequel(s).
My series is The Inquisitors’ Guild, a set of stories surrounding an investigative agency in the medieval(ish) city-state of Frosthelm. There is magic in Frosthelm, but few are skilled with it, and it mostly centers around objects that aren’t completely understood. There aren’t non-human races, but the world has a long history with complete with foreign nations and ancient cultures. The stories are a bit of a cross between epic fantasy and detective stories with some humor mixed in - kind of CSI meets Princess Bride.
The first book, Flames Over Frosthelm, centers around two young provisional inspectors assigned a minor case that rapidly becomes really complicated and implicates some important people in the city. The main character and narrator is Marten, a small, bookish guy with some limited talent with magic. He has a partner, Boog, who is large and strong and likes to thump things, but who’s also a shrewd detective. Their friendship is the heart of the story.
The sequels are not as sequel-y as in other series. Each of the later books has a different narrator (or two in the case of The Woeling Lass), and it covers a completely different case and investigation. In The Outcast Crown, the narrator is Boog (the partner from the previous book), and he takes on a new apprentice as his partner and trainee. She’s a bit of an outsider - an immigrant to the city who’s joined the Guild. They become embroiled in a deep mystery that draws in other members of the Guild and extends far beyond the borders of Frosthelm.
The Woeling Lass is the third in the series, although again, it’s stand-alone, and you can read them in any order without missing anything but a bit of backstory for the Guild and some of the characters. This book has two narrators. One an insufferable minor noble, Gueran, who serves in the Guild (and appears in the earlier books as a side character). At the start of the book, he and his family are targeted by an assassin, and he’s injured and quickly spirited away to a distant village, where he tries to heal and figure out what’s going on. His chapters alternate with an apprentice, Urret, who’s gotten herself in a bit of trouble, but who becomes involved with the investigation of the plot back in the city. From these two perspectives, we gradually learn of a mystery dating back centuries to a vengeful ghost who may or may not be real.
There’s also a novella, Traitors Unseen. It takes place about ten years before Flames Over Frosthelm. It centers around Emerra Denault, a provisional inspector who gets framed for a crime and has to go on the run to try to stay alive and clear her name.

Do you find that most of your readers continue to read the whole series? Why do you think that is?  
I’ve released the books relatively slowly, about one a year. Flames Over Frosthelm has certainly been read the most, but it’s been out the longest. I have a new compendium of the three novel-length stories, and a lot of people have been discovering that recently and burning through all three.

How difficult is it to add new characters in a sequel into already established relationships? 
That’s a little tricky, for sure, especially when friendships and relationships are important in earlier books. I cheat a little by having the stories be stand-alone and by picking a new narrator for each. We get to see the Guild and a new mystery from a different point of view, with previous characters sometimes present but not as a major focus. So, there’s development for those characters and their relationships, but not as much as if the sequels extended their original stories.

Is it difficult to continue with worldbuilding for a world you have already built in book 1?  Do you find it easier to switch locations for the sequel and start again with worldbuilding? 
I haven’t found that difficult yet, although the tricky part for me is remembering all the bits I’ve come up with in the earlier books and making sure the rules and people and places are consistent as I add on more. But it’s been a lot of fun to add onto my world. The second book explores the history of Frosthelm (and of some other countries) to a much greater extent than the first, and the third book goes much deeper into the governance and politics of the city. The prequel novella shows a little bit of the evolution of the Guild and the laws it enforces over time, and it shows the backstory of some of the characters who figure in the other books.

Have you ever been stymied by a worldbuilding or plot detail from book 1 that is very inconvenient to deal with or write your way around in subsequent books? 
For sure! In the first book, I gave the Inquisitors’ Guild a magical pool (the Augur’s Pool) that lets them use a magic ritual to see connections between objects and sometimes catch a glimpse of times where they’ve interacted. That’s a cool magic item and a fun premise, but it does make certain kinds of cases very easy to solve. That means in the later books, I have to sometimes come up with cases where it doesn’t help, or find ways that the people in the book are not able to use it to its full potential. It’s still fun, but it can make the plotting a little tricky.

Would you say your craft has improved with the subsequent books?
I hope so, although I’m proud of all of the books. The first one I worked on for over 14  years, and the others have come much more quickly, about a year each. I’ve tried to tackle some more complex issues, sometimes ones that relate to current concerns in the real world, in the later books. I have fun exploring the world and figuring out characters and plots that work. And, I love adding silly humor and fun relationships to make it a lot more entertaining.

Do you have all the timeline planned for the full series?
No, certainly not. I’m very much a seat-of-the-pants writer, which means I often don’t even know how a chapter is going to end, much less the book, much less a later book. I have written each book independently, and I don’t really have any grand plan, although I do like exploring the later lives of characters from the earlier books as I continue the series.

Do you have any marketing tips for sequels?
Incorporating the three books into a digital box set compendium has really helped sales, although I generally have to discount the box set to do a big marketing push. That’s worked for me twice with $0.99 sales. That kind of sale was the first time I was able to land a BookBub featured deal, and that’s been a tremendous boost in readership for the series. Marketing them individually has been a lot harder, although I do have some followers and fans who will read each new one as it comes out.
Thanks for the opportunity to do this interview! I really appreciate it, and I hope people will consider giving my books a try. You can find them on Amazon or on my site, https://davedobsonbooks.com.