Hi. Book IV is now available on Amazon on a pre-order basis.
As usual, though the official release date is October 12, 2018, the book will be released much earlier than the publication date. I always try to be conservative about such dates. A lot of things might happen – martian invasion, the zombie apocalypse, a massive solar flare, a world pandemic, and other such unexpected events. The book includes a brief compendium of lore covering notes, definitions, and maps from Books One to Three as well as those from the companion book of the series – Stories of Adar: Tales from the Abyss. Elements of the companion book serve as an introduction to some events in Book Four. The online version is but the initial draft – the final manuscript will have additional content due to the review and editing process. Lots of coffee could have something to do with it.
Amazon link: https://www.amazon.com/dp/B07FNHXG7B