The Burning Wheel: Monster Burner (2004)

From the back of the book:

Much more than a collection of monsters, this book is the essential tool for spawning your own creatures, traits, and lifepaths. Inside the Monster Burner are the detailed guidelines you need to understand and manipulate the Burning Wheel character burning system. Plus:

• Four new lifepath sets: Roden, Great Spiders, Trolls and Great Wolves, complete with new skills, spells and traits.
• Dozens of illustrated monsters! Some classic, like the Giant and the Dragon, and some unique, like the Chiropteran and Hsigo, but all steeped in that distinctive Burning Wheel flavor!
• Plenty of stats to peruse, as well as suggestions for integrating creatures into your existing campaign and for starting new ones with monsters.

Awards: Winner of the People's Choice and the Best Supplement award in the 2004 Indie RPG Awards