Writing Exciting New Levels of Heresy, it became apparent to me that Ayla was basically Nic and Mara's third, but a: Heresy was pretty narrowly focused on Mara's whole god thing and b: S2B2 stories need to have sexual content and Ayla is ace.
But I couldn't stop thinking about how their relationship would progress, especially since she'd be pretty involved in raising Nic and Mara's kids. Like, she does live with them. And she's very important to them, and vice versa. It's implied in Heresy that the reason Nic can fuck off with Mara to kill his priest/dad is that Ayla is managing the village--she directly enables their relationship to even exist.
This sequel story is actually longer than Heresy, lol. It also covers a lot more time, and they all have even less of a blueprint for how a polyamorous relationship with an asexual member works that it...takes a while to figure out.