This is an extremely high quality and thoughtful supplement that doesn't simply add more for the sake of it, but considers each Dark Lord on their own terms.

Perfect for quick access to dark lord stat block designed for serveral levels of play

Darklords of Ravenloft is a 61 page supplement that adds statblocks for the darklords in Van Richten's Guide to Ravenloft. More than just a simple listing of statblocks, this book also includes short introductions for the darklords and blurbs about the design philosophy behind each (which I especially appreciate). The darklords also have statblocks for 2-4 different tiers of play (1-5, 6-10, 11-15, 16-20), which makes this guide extra useful. My favorites were the additional statblocks for Strahd (in case you want to extend your Curse of Strahd campaign), and Ivana Boritsi, who would make for a unique tier 2 boss. Finally, the art and layout of this supplement are fantastic; this a well-organized and easy to read document. Overall, hats off to Wyatt Trull, Matthew Wulf, and Chris Hopper for making a great supplement.