This sourcebook describes supernatural beings such as demons, fairies, and ghosts, but also includes nightmarish flesh-and-bone creatures like the corpse-devouring ghoul, the foul pit worm, and the titanic gorger.

The wilds of Aventuria hold more than just monsters. The land also supports many dangerous and interesting animals. Aventuria's oceans, skies, and fields are home to bloodthirsty striped sharks, arrow-swift storm falcons, and heavily armored, horned saurians, each a unique challenge for heroes who dare to explore the trackless wastes.

Each creature description features a full stat block, a colorful illustration, and notes on physical traits, habitat, and encounter tips.

As a bonus, the Aventuria Bestiary introduces new advantages and disadvantages, new special abilities designed for combat with creatures, rules for creature swarms, and expanded rules for hunting and making use of quarry.