From publisher blurb:
Aquilae: Bestiary of the Realm is the largest, most comprehensive, most flexible, and most ambitious fantasy roleplaying bestiary ever conceived. 6,400 complete statblocks, comprising 1,600 monsters, each given the Quadded Statblock treatment, enabling them to be used in any campaign setting, with PCs of any level.
Add to this a thoroughly innovative and massively expandable AI system to guide monster behavior, and you have what just might be the most impressive and valuable creature resource ever to hit Pathfinder and 5E.
(Please note that Aquilae: Bestiary of the Realm in its entirety is a six-volume set. This publication is the sixth of those six volumes, and contains 1,064 statblocks comprising 266 monsters. This book may be used in combination with any number of the other volumes, or on its own.)
This book is intended to be any or all of the following:
An authoritative listing of monsters for use in any campaign setting, for adventuring parties of any size, and any level.
A means of using any existing monster with adventures of any level and difficulty.
A compendium of newly-created monsters, born of inspiration from existing beasties you may already know and love.
A single-source reference and repository, listing every single possible monster in easy-to-reference alphabetical order.