Official Defiance of the Fall Series & Theory Megathread

Welcome to the board. Zac and the Multiverse: theories, predictions and reactions for every volume of Defiance of the Fall. This is the standing megathread for the series: drop theories, predictions, favorite scenes and questions here, or start a new thread for anything bigger. Tell us how far you've read and what you're hoping to see next. House rules: tag spoilers with the book number (for example, "Book 7 spoilers") and keep to the reading progress you've set in the Spoiler Shield on each primer. Our book primers at /primers/ recap every published volume spoiler-bounded, so you can catch up without being ruined.