Van Richten's Arsenal Volume 1

From the back of the book:

Creatures of the night, be warned. Those who hunt the fiends that prowl the Dread Realms have the means to prepare themselves for whatever they face. Included herein are tools and techniques that allow the heroes of Ravenloft to take the fight to the next level. From potent spells to arcane artifacts, the secrets within these pages offer hope against the legions of darkness.

This book introduces a variety of new weapons to combat the fiends that populate Ravenloft. Included are rules for alchemy, new spells, magical items and new equipment. Prepare to bring down the forces of evil!