Why do dwarves and duergar hate each other? Why are there so many different kinds of elves? What lies at the heart of the Blood War, the great cosmic confrontation between demons and devils that threatens the existence of all things should one side ever be victorious? Mordenkainen knows these answers and more - and now you can find out too. This book is based on the writings of the famous wizard from the world of Greyhawk, compiled during a life dedicated solely to research and teaching. On his travels to other worlds and planes of existence, he made many friends and just as often risked his life to quench his thirst for knowledge. The first five chapters contain information for the game master to fill the cosmic conflicts described with life and content. Players will also find new material, including new player races. In addition to Mordenkainen's knowledge of the endless wars of the multiverse, this book contains game values for dozens of new monsters, including new demons and devils, new variants for elves and duergar, and a host of new creatures from the various planes of existence. For use with the fifth edition of the Player's Handbook, Monster Manual, and Dungeon Master's Guide.
