If you read this book before playing Shadowbringers , the reveal of the "Resonant" makes perfect sense. Zenos wasn't just crazy; he was following a logical, horrific research path laid out in a footnote on page 187.
For the walkers, Eorzea Encyclopedia Volume II is not a "coffee table book." It is a sacred text. It is the missing codex. And four years after the original Encyclopedia graced our shelves, this second volume—covering the tumultuous eras of Heavensward , Stormblood , and the lead-up to Shadowbringers —is arguably the most important lore drop the game has ever received outside of a patch note. eorzea encyclopedia 2
But if you are the type of player who wept at the end of 5.0, who cheered for Aymeric’s speech, or who wants to know the specific chemical composition of Ceruleum (it's a magical hydrocarbon, by the way), this is non-negotiable. If you read this book before playing Shadowbringers