I am really, really enjoying this series.

I started to see parallels with Dune books (I think also the second one). We're following leaders of nations or smth, they suspect each other of plots and such. Our main hero is someone who causes a tragedy. There's the resource for mind magic (calendar rather than spice).

And I really have a soft spot for both magic systems that call themselves mathematics, and for AIs who are underappreciated and great.

Oh, and not to mention books in series that have actual plot, events and things in the second book rather than "oh, we know you love the characters / world so we'll muddle along with nothing drastic happening".