Teres

And she also thinks that the Way of the Axe and the Plough and the racism are inextricably bound, which is... not how that works, either.

Not even close. Plus she thinks people will just magically forget about their religion the moment Axishit shows up and tells them to.

(Are Eurasian magpies best known for their song? It might well be.)

Seems they chatter rather than sing.

That is the first book of the DarkGlass Mountain trilogy, with StarDrifter and Axis back again, and with Ishbel, Isaiah and Maximilian. I am quite sure you have read it, since you once mentioned StarDrifter growing new wings.

I have indeed. Unfortunately. I think that was the point when I gave up on the series.