Available for free, much to Wexler's credit. Having read this first, I was pretty surprised that not only this storyline but this whole world basically doesn't intersect much with the main book thread, although it's happening more now as we get into the third book and the underlying structure of the world becomes apparent.

Flintlock wars in fantasy Arabia. I'm sure there's a load of depth I'm missing because I don't know much about history. That aside, all the characters are well-drawn here; Janus is a bit clichéd in that he's a genius who has his plans always work out and is all mysterious and nose-tappy and ahahaha about it, but that's fun to read, and he's nowhere near as egregious at it as, say, Eugenides. You do get the impression that the Redeemers are a bit crap and would have their arses kicked good and hard by, for example, the Krasians from the Desert Spear. Avoiding spoilers, I was not expecting the bad guy reveal at the end, which suggests that it was convincingly written.

The French Revolution. Even with my shaky grasp of history, the parallels are not so much parallel as this is just the French Revolution retold with the names filed off and new names written in in crayon. The books keep trying to be menacing about What Janus Is Really Planning; Wexler is on record as saying that he won't do a Janus PoV because it's hard to write from the perspective of a genius character, but honestly I think he won't do it because then we'll actually know whether Janus is really a villain or not. Mother vanishing offscreen was a bit weird, although I like the Steel Ghost's sand approach.