Exonomicon

Exonomicon is a fictional tome appearing in the tabletop role-playing game Pathfinder. It is described as a compendium of knowledge concerning the Outer Planes, the planes of existence that lie beyond the Material Plane. The Exonomicon is said to contain detailed information on the denizens, geography, and arcane properties of these planes, including the Abyss, the Nine Hells, and the Astral Plane. Its origins are attributed to the scholar Zerthimon, a legendary figure in the Pathfinder setting.

The Exonomicon is not a single physical book but rather a collection of writings and scrolls compiled over centuries by various adventurers, scholars, and planar travelers. Its contents are considered vital for anyone seeking to understand and navigate the complex and often dangerous Outer Planes. Information within the Exonomicon can range from the habits of specific demons and devils to the magical energies that permeate different planar environments.

In the context of Pathfinder campaigns, the Exonomicon serves as a lore resource for both Game Masters and players. It provides background material for adventures that take place on or involve the Outer Planes. Players might consult the Exonomicon to research a specific creature they are about to face, or to gain an advantage in understanding the rules and customs of a foreign plane. The tome's existence emphasizes the vastness of the Pathfinder cosmology and the wealth of knowledge that can be acquired through exploration and study.