
After finding out that Ambrose, Auri, Devi, Bast, and most of the mystery of the archives were not planned from the start, it now makes sense why there’s such a delay in Book 3.
These characters are pretty much the bulk of the story and he came up with them on the fly.
He’s probably struggling to figure out what to do with them since they weren’t intended for the endgame. Now his options are: Give them nothing and make them irrelevant, or try to work them into the finale without them feeling shoehorned in.
I still think it’s possible for him to do, but it definitely can’t be easy.