From the introduction: The "natural habitat" of the creatures in this book is Avadnu, the setting used by The Inner Circle’s Violet Dawn: The Time of the Unravelling line of products. Avadnu is a dark fantasy world suffering from the mistakes of its past, where more people are struggling to survive than attempting to rebuild. All creatures have sections describing how they fit into the world of Avadnu, and even DMs running games set elsewhere can use these sections as examples of how a given creature might fit into a world’s history.