In the historical fantasy Gods of Jade and Shadow (Del Rey, Aug.), a woman and a god undertake a magical quest across Jazz Age Mexico.

What inspired you to write a story set in post-Revolution Mexico?

I had the general idea for this novel maybe eight or ten years ago. A woman opening a chest, unleashing the god of death, a quest. I started some work on that with a contemporary setting. I dropped it after a little while. It didn’t gel. It was called Lords of Xibalba. Years later I began work on something completely different, set in the 1920s. That didn’t gel either, for other reasons. I liked the time period, because that’s the time period when my great-grandmother was young, and certain elements that were in there (travel by train, for example), so I decided to go back and see if I could cannibalize bits for a short story or some other project, which is not unusual for me. Eventually it occurred to me I needed to set Lords of Xibalba in the 1920s and my great-grandmother became my inspiration. She was an illiterate maid, and I wanted to write a story where someone who she could identify with would go on an adventure.

Casiopea’s adversarial cousin, Martín Levya, is an egotistical jerk. Why did you make him one of the narrators?

I find it hard to stop myself from switching points of view. In this case, it made sense because there is a running idea of duality and it was interesting to see the contrasts between these two cousins. Martín also allowed me to show the underworld, Xibalba, and the god Vucub-Kamé earlier on from a mortal’s perspective, which otherwise would remain veiled for almost the whole book. Finally, I think Martín becomes a more complex character when we can see into his head. From Casiopea’s point of view he’s just that jerk. And it’s not that he is nice when we are in his head, but we can see some of the cracks in him and some of the sources of his anxiety. We also experience how his interactions with a god are entirely different from Casiopea’s.

The gods, particularly Mayan death god Hun-Kamé, are strange and unknowable. What was the process of writing them like?

It was interesting writing someone who is not human, but who also can’t be completely alien. I liked the idea of giving the gods very florid speech patterns. The speech of lords is compared to jewels or flowers in pre-Hispanic cultures, and a scroll peeking out of the mouth is utilized to denote speech in pictorial representations, so when writing these characters, I kept going back to that imagery. They issue great speeches and proclamations and they are larger than life.