The sixth book in the Old Kingdom series is likely to be released in fall 2016. It has no official title as of yet, and is a "sequel of sorts" to Abhorsen.

According to a photo posted on Garth Nix's Twitter account, at least part of the story will take place six months after the end of Abhorsen and therefore around the time of The Creature in the Case as Lirael is still getting used to her new hand made by Sameth.